Frequently Asked Questions
Improved Partial Cloverleaf Recommendation
Q: The latest Improved Partial Cloverleaf alternative [presented at Public Meeting #2] does not require acquisition of residential property. What assurances do we have that this will hold true, and residential property won’t be acquired for this project in the future?
A: The EA is required to clear the maximum extent of impacts, or else the process would need to be revisited in the future. It is in the County’s best interest, and all stakeholders’ best interest, to show the maximum physical impacts in the EA. The EA will note that residential property impacts may include temporary construction easements.
Q: Since the recommendation is to improve the existing partial cloverleaf interchange configuration, what will change? Will the improvements result in any real time savings for vehicles traveling through the interchange?
A: The recommended Partial Cloverleaf interchange improvements will result in five lanes in each direction on Arapahoe Road under the I-25 bridge, elimination of the barriers that separate the existing lanes that lead to the I-25 ramps, allowing for a southbound triple left turn from the southbound off-ramp. Additional auxiliary lanes will also be added approaching the Yosemite and Boston/Clinton intersections and extending to the I-25 ramps. These improvements, when compared to the No Action alternative, show a significant benefit to traffic operations through the interchange complex.
Q: With the Costilla Crossing eliminated, are there still plans to widen Costilla to four lanes?
A: Widening Costilla Avenue will not be part of the I-25/Arapahoe EA project recommendations. With the Costilla Crossing eliminated, traffic forecasts would not warrant four lanes on Costilla, and improvements to Costilla would not address the Purpose and Need of this specific project.
Q: Now that the decision has been made to move forward with the Improved Partial Cloverleaf without Costilla Crossing alternative, will public comments still matter?
A: Yes, comments received at the second public meeting, and throughout the remainder of the EA process will have an impact on the process. Even though the one action alternative (Improved Partial Cloverleaf without Costilla Crossing) has been identified, the project is far from complete. Public input, along with the environmental resource impacts evaluation now being completed, will help define details of the final preferred alternative. Public input will help the project team determine which supplemental arterial roadway improvements should be made, if any, in the interchange complex. Members of the public can also suggest mitigation and enhancements, such as noise walls and landscaping improvements. Keep in mind that the preferred alternative could end up being the No Action alternative, which is still an option.
Q: If widening is necessary, why are we just hearing about it now [just prior to Public Meeting #2]? Is the addition of Arapahoe Road improvements at this point a way to circumvent the process?
A: The widening of Arapahoe Road has been a planned part of the Improved Partial Cloverleaf alternative all along. It is only recently that focus has turned to the details of the alternative instead of the interchange configuration as a whole. The Environmental Assessment process requires the project team to evaluate all reasonable alternatives, and identify the “footprint of maximum possible impact” (i.e. worst case scenario) of the recommended alternative as a starting point for further detailed analysis. Discussing details of the Arapahoe Road improvements is by no means circumventing the NEPA process, but rather the next step of the NEPA process being followed. Refinements to the design could not proceed until the Executive Committee agreed on the action alternative to move forward, which occurred on August 18, 2011. The project team then immediately started work to refine the design to minimize impacts to property, and this work will continue.
Q: Is there room for an eastbound barrier at the I-25 southbound exit ramp that would create a continuous green condition for I-25 ramp-bound traffic (similar to the existing barrier condition)?
A: In order to add a barrier separating eastbound through traffic from eastbound traffic bound for the I-25 on-ramps, approximately 10-15 feet of additional width would be needed under the I-25 bridge. The increased bridge length to span the wider section of Arapahoe Road would result in a deeper structure depth, resulting in additional reconstruction to further raise the elevation of I-25. Alternatively, lowering the elevation of Arapahoe Road would increase the grade on the I-25 on-ramps. The wider section would also shift Arapahoe Road further to the south resulting in a steeper grade than per design criteria for the southbound on-ramp, with potential undermining of the MSE walls along the adjacent LRT line south of Arapahoe Road.
Using the potential eastbound barrier for bridge piers, creating a three-span bridge, was considered but rejected. A three-span structure would require a similar structure depth as a two-span bridge, thus it would not provide any structural or roadway savings to the project. Constructing a three-span structure would also require constructing a pier in the center of eastbound Arapahoe Road, which would cause significant traffic impacts and delays during construction.
Operationally, the barrier would benefit eastbound traffic bound for the I-25 on-ramps the most since drivers could bypass the traffic signal at the southbound off-ramp intersection. However, the three through lanes north of the barrier would create a relatively narrow accepting area for the proposed southbound triple left turn, which could result in slower turning speeds. The slow turning speeds of the existing double left turning traffic is a contributing factor to the queues that currently develop on the southbound off-ramp.
The Improved Partial Cloverleaf alternative, as presently defined, would have five eastbound lanes at the I-25 southbound exit ramp intersection. The southbound triple left turn, with adequate turning speeds provided by the area of five accepting lanes, will allow acceptable off-ramp operations while providing the majority of the green time for each signal cycle to Arapahoe Road. The delays on the eastbound approach would be minimal, indicating good traffic operations through the intersection. The projected 2035 traffic operational analysis shows the level of service for traffic heading to the I-25 ramps would be LOS B or better in the peak hours. The projected 2035 queue lengths on the eastbound approach are expected to be relatively short with the average peak hour queues for traffic leading to the I-25 ramps at about 80 feet, which equals four vehicles or less. It is believed that the minimal delays expected for eastbound Arapahoe Road at the I-25 southbound exit ramp intersection do not warrant adding a barrier that could reduce the benefits to the southbound triple left turn and create design deficiencies.
Other Potential Improvements in Conjunction with Partial Cloverleaf Alternative
Q: What improvements does the City of Centennial have planned for Yosemite Street?
A: The City of Centennial has no plans for future widening of Yosemite Street beyond possible turn lane improvement at major intersections (e.g. right turn lane for southbound Yosemite at County Line Road). Centennial is currently in the process of developing a citywide Transportation Master Plan. If capacity is identified as an issue in this corridor, then alternatives would be presented as a part of the Transportation Master Plan (TMP) for public comment and input, and ultimately be presented to City Council for final action. Centennial expects to have additional information on the TMP in the first quarter of 2012, and hopes to complete the overall plan by the end of the year.
Q: Since pedestrian crossings add significant accumulation to intersections, and many pedestrians utilize the library (Uinta/Arapahoe light), what accommodations will be made for pedestrians versus traffic flow?
A: The study includes analysis of signal timing for all of the signalized intersections along the Arapahoe Road corridor from Quebec to Havana Street. The analysis will consider the balance in providing sufficient time for vehicles on Arapahoe Road and the intersecting street traffic, and pedestrians crossing the streets. Pedestrian grade separated crossing locations considered to date are at Yosemite and Boston/Clinton.
Pedestrian overpasses of Arapahoe Road at Yosemite Street and at Boston/Clinton Street have been suggested as a means to enhance pedestrian accessibility and safety. Eliminating the pedestrian phase from the signalized intersection timing could also benefit Arapahoe Road vehicular traffic flow, if this was feasible to implement. However, it is unlikely that a grade separation can be designed that would fit in the limited available ROW near these two developed intersections, and all at-grade pedestrian crossing physically controlled. East/west crosswalks would still exist at the intersections and any physical barrier to crossing Arapahoe Road at-grade would need to allow for the east/west crosswalk movement to access the Arapahoe Road sidewalk. Pedestrian count data indicates few pedestrian signal actuations now occur in the peak traffic hours, so the benefit to signal timing is negligible.
Q: Since the travel lanes are 11 feet on Arapahoe west of Yosemite why not carry the 11-foot lanes through the intersection and increase the width of the attached sidewalks since they are suppose to double as bike facilities.
A: The design team will consider options for increasing sidewalk width through the interchange complex, including reducing lane width from 12 to 11 feet. West of the interchange, lane width can be reduced upon agreement of the controlling jurisdiction, the City of Greenwood Village. East of the I-25 southbound exit ramp, Arapahoe Road is State Highway 88, so lane width reduction will need to be approved by CDOT.
Q: We believe Yosemite will likely carry more vehicles as a result of the changes to the I-25/Arapahoe Road interchange. Can residences beyond the 500 foot limit for inclusion of the noise reception study be included in the noise study and possible noise mitigation?
A: The traffic noise analysis is being conducted in accordance with CDOT’s 2011 Noise Analysis and Abatement Guidelines. The guidelines provide two criteria in determining the noise evaluation area. First is the project’s environmental study area or 500 feet from the proposed improvements. Second would be where a project does not physically alter a road but causes traffic on the road to at least double. (Note: doubling the traffic or noise sources equates to an increase of 3 decibels in sound level.) A traffic analysis has been performed for the EA project that examined both the No Action and the Action Alternative. The traffic analysis has shown that the traffic volume on Yosemite Street south of Arapahoe Road is not expected to change because of the project. Based on the information currently available, it is expected that the traffic noise conditions homes outside of this 500 foot area would be the same with or without the proposed improvements on Arapahoe Road. Recommendations for potential noise mitigation for homes along the project limits are now being finalized and will be defined in the EA document.
Q: Has the County initiated any property owner communications regarding proposed right of way acquisitions?
A: No. The County has not made any property owner contacts regarding right of way acquisitions. This would be premature since a preferred alternative has not been determined or approved by the Federal Highway Administration, and final design has not been completed to identify the extent of right of way required.
Q: If applicable, when would property acquisition happen?
A: Right of way acquisition would occur at the earliest in 3 - 5 years assuming funding was in place. As soon as the EA is approved, then federal funds can be used for acquisition if money is in hand. Final design would need to be completed prior to property acquisition.
Q: Would eminent domain be used to acquire property for the proposed improvements?
A: Eminent domain takes effect only as a last resort, after the establishment of fair market value through the appraisal process. In cases of eminent domain, the court determines the property value if the agency/project sponsor and property owner cannot agree. It is unknown as to who will be the sponsor of the project in the future. The project sponsor typically makes the decisions regarding eminent domain on any project. Eminent domain can’t be used for urban redevelopment, and would not be used by a city to acquire land for redevelopment to increase tax base.
Q: How will this project affect property values?
A: The proposed improvements will relieve traffic congestion associated with regional growth, provide a safe and convenient east-west route for pedestrians and bicyclists and increase emergency vehicle circulation. Noise, traffic and other potential impacts to nearby residents and businesses will be analyzed and mitigated where warranted. Other enhancements will also be considered related to the context and character of the area.
Q: What is the plan to mitigate impacts to the Walnut Hills neighborhood?
A: Environmental and community impacts will be identified through the EA process, including analysis of air quality, noise, visual and traffic operations. Options will be considered for necessary improvements to surrounding roadways, aesthetic treatments consistent with the character of the area and noise abatement if warranted.
Q: How are noise and air quality being considered during alternatives evaluation?
A: Alternatives analysis includes studies of these issues and consideration for mitigation. Once the traffic volume forecasts are completed, the noise and air quality models will be run. Noise monitors will be put out to establish a baseline, and traffic projections are fed into the noise model which is factored to address any geometric change. Then, mitigation options are determined.
Q: Why is Greenwood Village not making improvements to handle the traffic generated by their office parks?
A: Greenwood Village has focused on safety and accessibility within the commercial area for many years. There have been numerous capital improvements made in conjunction with new development, projects by Greenwood Village, and capital investments from districts and other agencies. Within the last 10+ years, Greenwood Village has expended over $16 million towards capital improvements and programs to improve traffic along and within the corridor, most projects with the intent/goal to relieve traffic demands at the Arapahoe / I-25 interchange. This has included improvements for the creation of the "serpentine road," specifically intended to relieve demands at the Arapahoe / I-25 interchange by diverting traffic to the north, Arapahoe/Boston/Clinton intersection improvements, as well as significant support towards mass transit and availability of alternate modes of transportation. Based on the current Capital Improvement Program, an addition $7 million has been identified for projects within the same area and include improving signal systems to optimize capacity of the existing roadway system.
Q: Why not simply complete the previously planned improvements by Greenwood Village to the "Serpentine Roadway", providing an alternative to traveling Arapahoe Road, via Havana north to Peakview, north on Boston, then west on Caley to Yosemite Street and south to the Yosemite Street overpass? Wouldn’t this be sufficient to accommodate future traffic?
A: Completion of the previously planned sweeping curve between Boston and Caley may entice a small amount of additional traffic to use this existing four-lane alternative to traveling Arapahoe Road. This route has been considered in the travel forecasts and operational analysis of future conditions and found to be insufficient in accommodating future interchange traffic.
Q: Can the general origin and destination of traffic through the interchange be estimated in order to confirm that proposed improvements are consistent with travel desires and needs?
A: During the Arapahoe Road Corridor Study, analysis of the 2030 traffic forecasts of the Costilla crossing showed that a high proportion of users would be drawn from the immediate vicinity, with more than 50% of the trips coming from the area between Quebec Street and I-25 on the west side and more than 60% of trips coming from the area between I-25 and Havana Street on the east side. This travel origin data will be updated once the 2035 traffic forecasts are completed.
Q: What constitutes cut-through traffic?
A: Cut-through traffic is generated by a trip with the sole purpose of avoiding nearby congested streets and intersections, coming from and going to outside the neighborhood, with no purpose/destination in the neighborhood. School related traffic is not considered cut-through, since it has a destination within the neighborhood.
Q: How will cut-through traffic be addressed?
A: As part of the EA, a study of existing cut-through traffic in the Walnut Hills neighborhood will be conducted in the spring of 2011. The City of Centennial would be responsible for mitigation of existing cut-through traffic, if applicable. The City of Centennial’s Neighborhood Traffic Management Program (NTMP) requires ten percent of existing traffic to be cut-through traffic in order to meet the threshold for TMP scoring and rank for mitigation. Most mitigation applications in the City are related to a combination of speed, accident and volume issues. If the issue is only cut-through volume, it would not likely score high on the NTMP.
Mitigation for any future cut-through traffic would not aim to fully eliminate cut-through traffic volume, but mitigate increased cut-through traffic impact if caused by the project.
Q: Will the proposed interchange design improve interchange Level of Service (LOS)?
A: Previous traffic analysis indicated that the interchange improvements alone would result in congested traffic conditions within the interchange in 2030. A supplemental east-west crossing of I-25 could help divert sufficient traffic volume from the interchange to improve its projected LOS. The EA will be based on new 2035 traffic forecasts and analysis to confirm the need for more than just the interchange improvements. Evaluation of the No Action alternative will also be included to document and contrast the benefits and impacts of the proposed improvements.
Q: It seems that most of the traffic causing backup onto I-25 is heading east, and that part of the problem is caused by the number of traffic lights east of I-25. Also, improving the Quebec intersection would help solve the I-25/Arapahoe intersection problems.
A: It is clear that the interchange functions as a complex, and for the purposes of this project the complex is considered the segment of Arapahoe Road from Yosemite to Dayton. However, traffic counts were collected as far west as Quebec, and regional traffic is considered in the study. The Arapahoe Road Corridor Study made recommendations to remove some traffic signals by constructing grade separated interchanges (including Havana), but it was clear during that project that removing all signals would essentially turn Arapahoe Road into a freeway, and this was not desired by the corridor agencies or public. Removing some signals would be part of the long-term solution, but signal timing adjustments will be investigated as a short-term solution. A major cause of the backup is the barrier and pier locations under the I-25 bridge that results in slow double left turns southbound to eastbound from I-25. Providing three left turns would greatly help operations at the southbound off-ramp.
Q: Who closed Jordan Road and why?
A: Jordan Road was closed during the I-225/Parker Road construction project. That project needed to take land from the park, and it is a federal requirement to replace that land by giving the park other land. Jordan Road was the trade.
Q: Is the outcome of the EA already determined? How can money be allocated for the project before a decision on the ultimate improvement is made?
A: No, the preferred alternative has not yet been determined. Please refer to the EA process graphic (on the home page of the project website) for a description of the steps that have been and will be taken prior to determination of a preferred alternative. The project cost estimate based on the Feasibility Study recommendation is used a place saver for the DRCOG Region Plan, with specific details of the planned improvement to be determined through the EA process..
Q: Was it premature to submit a request for Congressional support for the proposed Partial Cloverleaf Interchange Improvements with Costilla Crossing prior to completion of the NEPA evaluation and FHWA approval of the preferred alternative?
A: Since a number of Congressionally-designated projects have encountered roadblocks and dead-ends because the project description within the authorizing and/or appropriating bill was either not clear or complete enough to allow necessary work to move forward, it was requested that the federal discretionary highway funding request include the following language: "I-25 & Arapahoe Road (SH 88) Interchange Reconstruction Project - Arapahoe County, Colorado. Project should incorporate necessary studies, design, right-of-way acquisition, utilities, & construction of a phase of the EA and FONSI approved alternative." Alternatives for interchange improvement with and without the Costilla crossing will be evaluated in the EA.
Q: How are the current operational improvements at the interchange being accounted for? Why don’t you wait to see how they improve the situation?
A: The improvements under construction during the spring and summer of 2010 at the I25/Arapahoe Road interchange are being considered in the No Action alternative as being completed. Alternative improvements identified in the EA process will be compared to operations with the current improvements in place. Analysis of traffic operations with 2030 forecasted volume indicated that the current improvements would be insufficient, resulting in congested traffic conditions unless additional improvements were made. This finding will be reconfirmed with new traffic count data and analysis of the 2035 travel forecasts for the EA.
Q: How effective is public feedback during an EA process in shaping the improvement recommendation? It is a concern that government agencies will move ahead with improvements regardless of public input.
A: Improvement plans for many projects have been modified to address issues raised through the EA public input process. Roadway alignments have been adjusted, mitigation of community impacts included, and phasing of construction adjusted to respond to community and agency concerns. Examples include noise mitigation and LRT station design modifications along I-25 south during the TREX project in response to public concerns, and the southeast quadrant ramp design at the planned Arapahoe/Parker interchange for consistency with Town of Foxfield development plans. The ultimate design of improvements for the I-25/Arapahoe project will incorporate context sensitive design features consistent with community character. NEPA requires that public input be considered during the EA process.
Q: How will alternatives be evaluated?
A: Decision-makers will inherently be faced with considering tradeoffs during the EA process. The EA will determine impacts (potentially both adverse and beneficial) of various interchange improvements. Consideration of traffic operations, planned and on-going land development, the environment, and community values, as well as following sound engineering standards, will shape the alternatives. The alternatives will be evaluated for consistency with the purpose and need and objectives of the project. The determination of a preferred alternative will involve comparing the tradeoffs among the various alternatives as well as a review of the public comments. NEPA requires that a No Action alternative be fully considered in the EA in addition to any action alternatives. All public and agency comments will be considered. The EA document will include a summary and outcome of this process and the identification of a preferred alternative.
Q: What will happen after this EA is concluded if a Finding of No Significant Impact (FONSI) is made by FHWA?
A: Local agencies will likely incorporate the preferred alternative into their transportation and comprehensive plans. The results of the study will provide information to support decision maker’s efforts to identify and obtain funding for planned improvements.
Q: Who makes decisions regarding the EA?
A: FHWA and CDOT ultimately are responsible for the decisions to identify a preferred alternative in this EA. However, they will consider all input and comments from members of the public, local agencies and other stakeholders when making any decision.
Q: What is the implementation timeframe for improvements recommended by this EA?
A: This Environmental Assessment is a 30 month project. The timeline for physical improvements is dependent on funding availability. Currently, $83 M of federal funds are allocated for the project. Most likely, the earliest improvements could be constructed is five years from now (if the federal funding and estimated shortfall funds were in place). It is more common for projects of this magnitude to take 10 - 15 years to complete, and likely be constructed in phases. A comparable example project is the Arapahoe/Parker Interchange project. The EA for that project was completed in 1998, and the final phases of construction are planned to be complete next year (almost 15 years since study inception). Phasing of improvements at I-25/Arapahoe is likely since funding would not be available all at once.
Q: What specific metrics will be used to measure success of the improvements chosen?
A: The measures of success will be directly related to how well the improvements meet the project objectives listed below:
- Accommodation of multi-modal travel demand.
- Compatibility with existing major infrastructure, particularly the Southwest Corridor LRT.
- Sensitivity to residential impacts and preservation of community character.
- Context Sensitive Solutions (CSS) that reflect community character.
- Mitigation of adverse impacts.
- Recognition of the economic importance of the interchange at the local and regional levels.
- Affordability considering anticipated construction and right of way acquisition costs, and the potential for funding availability.
Q: Why were commercial properties west of Yosemite notified of the Arapahoe Road Corridor Study but residential properties were not included?
A: The Corridor Study mailing list included properties within approximately one quarter mile of the entire corridor limits extending from I-25 east to Parker Road. This mailing area did not include individual parcels within Walnut/Hunter’s Hills. However, effort was made to inform these neighborhoods through the HOA/neighborhood organization. Three meetings were held with the HOA "Community Resource Panel" (CRP) focus group during the corridor study. The HOA contacts were mailed project correspondence on public meetings and invited to all of the CRP meetings, with a request to disseminate project information to their residents. The Walnut Hills contact never responded to the formal request to be a part of the study. Since it was not possible to mail directly to everyone that may be interested, an attempt was made to involve the HOA contacts and news releases were sent to local media and agency PIOs. The Corridor Study direct public mailings notified parcels very near the corridor, knowing the parcel mailing area would be expanded when individual projects moved forward. The mailing list has been expanded for the ongoing Environmental Assessment project to include all of the Willow Creek and Hunters Hill neighborhoods.
Q: The first EA public meeting was held on April 15, 2010, income tax deadline day. Was this date picked hoping for low turnout?
A: The public meeting held April 15, 2010 had exceptional turnout. Approximately 230 people attended. The meeting was held in an open house format from 4:30 to 7:00 PM, allowing the public the opportunity to stop in early or late, depending on their personal schedules that day. It should be noted that this level of attendance is nearly double the number attending the first Corridor Study public meeting, so holding it on "tax day" doesn’t seem to have been a deterrent, nor was it ever intended to be a deterrent.
Q: When is the deadline to submit new suggestions for interchange designs/improvements?
A: Technically, newly suggested reasonably feasible alternatives will be considered until the decision document is signed by FHWA at the end of the project. However, the project team is confident that with over 20 alternatives and options already being considered, all feasible alternatives have already been suggested. It is likely that any further suggestions would be a variation of an alternative already being investigated.
Q: Who hired DEA?
A: Arapahoe County is the contracting agency, with funding from STP-Metro (Federal funds), Southeast Public Improvement Metro District, Arapahoe County, Greenwood Village and Centennial.
Q: Will the project documentation include a "Transportation Discipline Report", as prepared on a recent project in Washington State?
A: The Interchange and Supplemental I-25 Crossing Alternatives Technical Report, now being prepared in conjunction with the I-25/Arapahoe Road Interchange Environmental Assessment is very similar to what is referred to as a Transportation Discipline Report in the state of Washington. Washington is one of sixteen states that have enacted a State Environmental Quality Act (SEQA). These acts generally mirror the federal NEPA process and contain similar provisions. Washington State has adopted the term "discipline report" to refer to resource and technical analyses prepared in conjunction with an Environmental Impact Statement. An example is the Transportation Discipline Report prepared in 2005 for the SR 520 Floating Bridge Replacement project, a multi-year, highly controversial assessment of replacing the bridge across Lake Washington between Seattle and Bellevue, Washington.
Similar to the Transportation Discipline Report, the I-25/Arapahoe Alternatives Technical Report contains key findings of travel forecasts, traffic operations analysis, constructability, impacts identification and mitigation considerations. The report will be posted on the project website once it is reviewed by the project Technical and Executive Committees.
Q: Are other supplemental crossings of I-25 north of Arapahoe Road being seriously considered?
A: Alternative I-25 crossings north of Arapahoe Road at Caley Avenue and at Peakview Avenue have been considered. Due to the distance away from Arapahoe Road and redundancy with the nearby Yosemite Street overpass, the alternatives would divert little traffic from Arapahoe Road. The Peakview crossing was also found to be physically infeasible to construct and meet maximum desirable grade to cross over or under I-25 without major reconstruction of intersecting streets and intersections.
Q: What is the logic behind the Costilla underpass as part of the interchange improvements?
A: The concept for a Costilla Avenue crossing was developed during the Arapahoe Road Corridor Study as a means to potentially divert traffic from the I-25/Arapahoe interchange, thereby improving interchange traffic operations. The Costilla connection offered several advantages over other potential crossing locations:
- I-25 is slightly elevated at the proposed crossing allowing for an underpass to meet minimum design standards for vertical grade.
- Connectivity with Costilla Avenue to the east provides a nearby parallel east-west route as an alternative to Arapahoe Road.
- The proposed alignment would intersect with Yosemite Street about 500 feet north of the Briarwood Boulevard/Alton Way intersection within an established business area, offset from the Walnut Hills residential neighborhood street network. Alternative intersection design would be considered to promote the new east-west connection and de-emphasize additional north-south travel on Yosemite Street south of Alton Way.
- The Costilla crossing would not add substantially to traffic at the Arapahoe/Yosemite intersection since it would also provide an opportunity for traffic on Yosemite Street south of Arapahoe Road to avoid the intersection.
Q: Why was the Improved Partial Cloverleaf with Costilla Connection alternative shown in the project discussion materials?
A: The improved partial cloverleaf alternative is the interchange improvement recommendation from the System Level Feasibility Study, completed in December 2008. Numerous other interchange alternatives were previously considered. These were presented at the first public meeting and will be documented in the EA.
Q: What are the plans for development of the southwest quadrant of the interchange, and would a supplemental crossing of I-25 benefit this development?
A: The City of Centennial sub-area plan in this quadrant of the I-25/Arapahoe interchange identifies this area for potential commercial redevelopment (Arapahoe Urban Center). The plan can be reviewed on the City of Centennial website under the Land Development Code Re-write documents. A supplemental crossing could improve area mobility, but would need further study to determine benefit versus community impacts.
Q: Why can’t the necessary improvements be made all at Arapahoe Road and I-25 without involving other nearby streets (such as providing an underpass of Arapahoe Road from Yosemite to Boston/Clinton)?
A: In conjunction with the Arapahoe Road Corridor Study conducted in 2007, the concept of an Arapahoe Road tunnel beneath the I-25 interchange was considered. The tunnel was part of a three level diamond interchange concept that extended between the Yosemite and Boston/Clinton intersections. Further extension under the Yosemite/Arapahoe and Boston/Clinton/Arapahoe intersections was noted as a consideration if the amount of forecasted through traffic was substantial. However, this concept was not recommended for further consideration due to several factors:
- The amount of through traffic is not as substantial as the high percentage of traffic turning onto and off of Arapahoe Road at I-25, Yosemite and Boston/Clinton.
- Substantial walls, bridges and drainage accommodations would be required along Arapahoe Road to separate the through movements.
- Focusing all necessary improvements to accommodate 2035 traffic on Arapahoe Road would require Arapahoe Road to essentially become a freeway, which is not consistent with community vision or character of the adjacent business community.
- Construction cost was estimated two to three times that of the improved partial cloverleaf concept.
- Ultimate approval of the proposed improvements by FHWA requires that a plan for sufficient funding be in place. Currently, only $83M has been identified for the interchange improvements in the DRCOG Regional Fiscally Constrained Plan, substantially less than the estimated cost of a three level interchange.
Q: Are improvements being considered at other DTC area interchanges to the north?
A: The Orchard and Belleview interchanges have also been considered for improvement by local agencies, and a study is soon to be initiated by the City and County of Denver, Greenwood Village and Arapahoe County for improvements at the Belleview interchange.
Q: Why is a supplemental through movement from the southbound ramp to the southwest quadrant eliminated from further consideration?
A: CDOT and FHWA have commented that this movement could possibly be considered if a redevelopment plan was certain. Currently, marginal benefit is seen by allowing this movement versus the major cost of the improvement. Further analysis would be needed to determine if this through movement would operationally help interchange traffic operations and at what development level. This land use scenario (with and without a major redevelopment according to city’s master plan) will be tested in the model as a potential "high growth" scenario.
Q: Since much of the interchange problem is related to south to east traffic flow turning from I-25, why not consider fly over ramps?
A: Alternatives with directional ramps (fly over and under) were considered in the previous studies and were displayed at the first public meeting. They were previously eliminated from further consideration due to physical constraints presented by the TREX highway and LRT improvements and the proximity of nearby intersections (Yosemite Street and Boston/Clinton) restricting ramp traffic operations.