The Washington State Department of Transportation (WSDOT) reviewed the environmental implications of opening freeway high occupancy vehicle (HOV) lanes during off peak hours. The review explored:
• Commitments contained in environmental review documents completed at the time of HOV lane construction. These commitments could have implications that impact any change decision.
• Types of environmental analysis that would be suggested as part of a change decision.
• A preliminary assessment of potential environmental impacts of opening HOV lanes during off peak hours.
What did the review conclude?
Environmental impacts minor or non-existent
Based on analysis to date, environmental impacts from opening freeway HOV lanes to general-purpose traffic in off-peak hours are minor or non-existent.
Some additional environmental review and documentation required
Further environmental review and documentation will be required if a proposal to change HOV lane hours of operations is adopted. This would include a review of air quality, habitat for threatened or endangered species, and social impact analysis, including "environmental justice" consideration. Preliminary review of these factors reveals no likely impact. It is anticipated that both a National Environmental Protection Act (NEPA) Documented Categorical Exclusion and State Environmental Protection Act (SEPA) Categorical Exclusion would be the appropriate level of documentation for the proposed action regardless of the alternative selected.
No environmental commitments preclude conversion to part-time operation
A review of environmental documents for WSDOT freeway HOV projects found no commitments that would preclude the conversion of freeway HOV lanes to part time operation. However, the I-90 operating agreement would require concurrence from the signatory agencies if the I-90 center roadway operation were proposed for changes. This section of the HOV lane system, however, has already been downgraded for further consideration as a candidate for general-purpose traffic on nights and weekends.
Air quality impacts negligible; coordination with Department of Ecology necessary
Some freeway HOV lanes were included as Transportation Control Measures in the 1987 State Implementation Plan (SIP) for Air Quality. Since that time, the Puget Sound region has come into compliance with federal air quality standards. A preliminary air quality analysis by the Puget Sound Regional Council for the daytime option (the only time period which is able to be modeled) would result in minor increases in emissions, but well within the air quality emissions budget - indicating no air quality conformity issue with this option. While not specifically modeled, indications are that night and weekend openings would have less air quality impacts than daytime openings, and therefore negligible impacts on the region's air quality. Further coordination with the Washington State Department of Ecology (WSDOE) is needed on whether SIP changes would be required.
What assumptions regarding HOV lane hours of operation have been included in environmental documents?
No single database listing environmental commitments exists for WSDOT freeway HOV lane projects. Therefore, information regarding the original HOV projects was collected from various resources including the WSDOT Northwest Region documentation program library and interviews with former HOV design staff and engineering managers. The majority of these HOV projects were built with the assistance of federal funding. However, it was also determined that Federal Highway Administration (FHWA) Washington Division does not have a database or source that maintains a record of environmental commitments for federal-aid projects.
A list of original HOV lane projects noting the FHWA Federal-aid and project agreement numbers has been reviewed. Based on this review, the following specific commitments were identified that may be pertinent to the decision to change HOV hours of operation. However, none of these commitments would preclude a change to part time operations.
Interstate 90
- Memorandum Agreement, December 1976 (cities of Seattle, Mercer Island, and Bellevue; King County; Metro; and the Washington State Transportation Commission): These parties signed an agreement related to construction on I-90 between I- and I-405 (Seattle to Bellevue). Part of this agreement included the following HOV-lane-related provisions:
i. Metered and controlled local access to I-90 east of Bellevue during peak hours
ii. Transit/carpool lanes and/or Surveillance Control and Driver Information Systems (SC&DI) on I-5 from I-405 at Tukwila to the King county Snohomish county line
iii. King County Metro park-and-ride lots and flyer stops in the approved 1980 plan
iv. Provision for a bus way or exclusive transit/carpool lane(s) and/or SC&DI as part of SR 520 from I-5 to I-405
v. The redesigned SR 520 and I-5 interchange, and Mercer Street egress from I-5 for improved transit flow and congestion relief between I-5, Mercer Street and Roanoke Street
vi. Provision for a bus way or exclusive transit/carpool lane(s) and/or traffic control measures as part of I-405 from Bothell to Renton
vii. Provision of exclusive transit lane(s) on I-405 through Bellevue, which also included a freeway flyer stop, and a park-and-ride facility on I-405 between Main Street and NE 8th Street in the Bellevue central business district.
Interstate 5
- SR 516 to South 188th, Southbound and 320th Street/Military Road to Tukwila, Northbound:
Interstate classification of these segments requires full standard design of the facility from interim HOV lane status when funding becomes available. HOV lane segments from NE 145th to NE 200th also require appropriate full standard design.
- HOV Improvements: Olive Way to SR 520, Environmental Assessment:
Lane closures limited to off-peak hours.
- Tukwila to Mercer Street Transit/Carpool Improvements Environmental Assessment:
The document acknowledges the construction of transit/carpool lanes on I-5 from Tukwila to Mercer Street as one of the committed transportation control measures in the WSDOE State Implementation Plan to which commitment was made to bring the Seattle/King County area into air quality compliance by 1987.
Interstate 405 (I-405)
- Memorandum Agreement, December 1976 (cities of Seattle, Mercer Island, and Bellevue; King County; Metro; and the Washington State Transportation commission):
Also see listing under I-90, item 1 above.
- The following list of documents acknowledges the construction of transit/carpool lanes on I-405 as one of the committed transportation control measures in the Washington State Department of Energy State Implementation Plan whence commitments were made to bring the Seattle/King County area into air quality compliance.
i. South Renton Interchange to Sunset Boulevard Final Environmental Impact Statement
Total length of I-405.
ii. Tukwila to Sunset Blvd. Transit/Carpool Improvements Environmental Assessment
I-405 from Tukwila to Sunset Boulevard.
iii. SR 900 to I-90 (North Renton Interchange to Factoria Interchange) HOV Improvements Environmental Assessment
I-405 from Renton to Factoria.
- Northup to Bothell: Interstate classification of this segment requires full standard design of the facility when funding becomes available.
Sound Transit Direct Access Projects
As a condition of receiving FTA funding for direct access projects, Sound Transit has entered into undertakings of "continuing control"; that is, the facilities funded will be operated for the purposes for which the grants were given over the useful life of the facilities. Any changes in the operations of the HOV lane system must not violate the assurance that the direct access ramps will be operated in accordance with the continuing control requirement.
What are the air quality impacts if HOV lanes were opened to general-purpose traffic during off-peak hours?
The Puget Sound Regional Council (PSRC) has provided regional modeling and analysis for changes in traffic use and operational patterns of the HOV lane system that would result from liberalization of midday HOV restrictions. This analysis was conducted to determine compliance with air quality maintenance areas and conformity with the Air Quality State Implementation Plan. The report shows that there would be little change in air emissions as a result of HOV hour change for the midday option, and that there would be no resulting problem meeting the current regional emissions budgets. We anticipate that air quality will remain within future emissions budgets that will be developed as new modeling assumptions are developed.
PSRC's regional model is not able to forecast traffic or emissions during night or weekend off-peak periods. However, it can be assumed that any emissions changes for the night and weekend change options would be less than midday, when traffic and congestion is higher. Since the midday analysis does not indicate an air quality conformity problem, it is logical to conclude that the night and weekend change options will have less of an impact, and therefore no air quality conformity impacts.
The opening of HOV lanes to general-purpose traffic during off-peak periods would not trigger the need for a local "hot spot" conformity analysis under current federal regulations since no areas of frequent human use will be affected. In other words, there are no sidewalks or pedestrian areas within the freeway HOV areas under consideration.
The State Implementation Plan (SIP) for Air Quality included some HOV lanes as transportation control measures. However, where regulatory commitments were made the conditions apply to HOV use during peak periods. Since the change options under consideration would not affect peak period operation, compliance with the SIP would not be affected.
What level of environmental documentation would be required if HOV lane operations were revised?
Documented Categorical Exclusion (DCE) may sufficiently analyze operational change of the existing HOV lane system to general-purpose. Any of the hours of operation alternatives under consideration would be considered NEPA Class II actions because the proposed action will not individually or cumulatively have a significant environmental effect.
In addition, state funding for the action will require completion of an Environmental Review Summary (ERS) to identify the action as a SEPA Categorical Exemption (CE). Of the twenty-one areas of environmental impact under NEPA, the action proposed by any of the alternatives will likely not result in substantial impact to environmental resources. A NEPA DCE is appropriate to analyze potential effect on federally listed threatened and endangered species required by Section 7 Endangered Species Act, and to analyze and document air quality conformity.
Preparation of the NEPA DCE and SEPA CE would involve approximately a month.
Following are the elements and a brief description of the tasks needed to complete the DCE and CE documentation:
Environmental Review Summary
A region permit coordinator could complete an environmental review summary (ERS) within one week. The ERS is a tool to identify areas of impact and to secure FHWA concurrence for the appropriate level of NEPA documentation in accordance with 23 CFR 771.117. The ERS will identify the action as a class II DCE. The same form will also identify the SEPA concurrence for the action as a CE. The permit coordinator would further complete and submit a SEPA non-project level SEPA checklist and Determination of Non-Significance (DNS). The SEPA checklist would be processed by WSDOT as the SEPA lead agency. Upon receipt of the SEPA checklist and proposed DNS the WSDOE would review and issue the DNS within a 14-day period.
Air Impact Analysis
WSDOT staff would prepare an air quality evaluation to describe the affected environment. Puget Sound Regional Council has performed regional modeling of air quality impacts where possible.
Endangered Species Act
Compliance WSDOT staff would request the Threatened and Endangered Species listings from the United States Fish and Wildlife Service (USFW), National Marine Fisheries Service (NMFS), Washington State Fish and Wildlife Service and Washington State Department of Natural Resources. NMFS information is obtained from their web site, not by correspondence. The biologist would undertake the biological evaluation (BE) process and a preliminary No Effect letter would be written. The No Effect letter is a package of text and graphic exhibits including vicinity map and plan sheets. The No Effect letter is reviewed by the biology staff manager and forwarded to FHWA and USFW. This process can usually be completed within one week.
Social Impact Analysis (including environmental justice consideration)
WSDOT staff would administer a consultant contract to analyze census and demographic data of minority and low-income populations existing in the action area. The consultant would conduct any public outreach to target populations, to glean issues of potential concern. Other WSDOT staff may be available to perform the analysis. The test for disproportional effects will be based on the analysis of area demographic profiles, or the U.S. Environmental Protection Agency's (USEPA) Draft Revised Guidance for Investigating Title VI Administrative Complaints Challenging Permits (Draft revised Investigation Guidance) (USEPA, June 2000). Two to three standard deviations above the mean are suggested by the guidance as a quantitative measure of disparate effect. This process takes about one week.
Documentation Review
WSDOT staff would guide and consult with project staff during preparation of the documentation, review the products, and provide approval signatures where appropriate before submitting the environmental review summary to FHWA for signature approval. Two days should be sufficient to complete this task.
What are the likely environmental impacts of opening HOV lanes to general-purpose use during off-peak hours?
The following discussion about potential environmental impacts of each alternative is, in part, based upon data from University of Washington Transportation Research Center freeway HOV lane studies completed in 2000.
Option 1 - nights (8:00 PM to 5:00 AM)
The biological evaluation process for Section 7 ESA compliance would provide the analysis to conclude any potential for adverse impact to wildlife habitat, and threatened and endangered species. Though there is typically more wildlife activity at night, no adverse impact is anticipated by increased operation of the core system HOV lanes during nighttime, off-peak hours. Disproportionate effects to minority or low-income communities are not anticipated by this option. Air quality impacts, while not specifically modeled, are expected to be lower than the midday modeled results, and therefore not a compliance issue.
Option 2 - midday (9:00 AM to 2:00 PM)
Study data indicates traffic is generally free flowing on freeway HOV lanes and general-purpose lanes during the midday, with the exception of spot location general-purpose lane congestion. No adverse impact to wildlife habitat, and to threatened and endangered species is anticipated beyond what existing conditions present. ESA Section 7 compliance will provide the analysis to conclude no effect conditions. This option may carry the potential to slightly, disproportionately affect minority or low-income communities, but the data needed to make this determination is not presently available. Air quality modeling by PSRC indicates a minor shift in emission levels if HOV lanes were opened to general-purpose traffic midday. But, the expected change is well within the region's emission budget; therefore, there is not an air quality compliance issue.
Option 3 - weekends (8:00 PM Friday to 5:00 AM Monday)
The traffic study data of core system HOV lane use during weekends conclude no relative change in existing congestion patterns, or highway system performance. Operational changes to the system will not affect wildlife habitat or threatened and endangered species habitat any differently than currently exists. Additionally, there are likely no indirect affects to habitat resulting from the indirect changes in traffic congestion patterns and highway system performance posed by this alternative to the adjacent highway system. ESA Section 7 compliance will provide the analysis to conclude no effect conditions. Disproportionate effects to minority or low-income communities are not anticipated by this option. Air quality impacts are expected to be lower than the midday modeled results, and therefore not a compliance issue.
What, if any environmental mitigation would be required?
No adverse impacts to wildlife habitat, or threatened and endangered species are anticipated. Therefore, no environmental mitigation requirements would be expected.
There is thought to be little potential for substantially disproportionate effects to minority or low-income communities.
The potential for air quality impacts are not anticipated at this time. Previous documentation by the PSRC had indicated that air quality could be of concern with the HOV hour change options, but current modeling and analysis indicate that only a very slight change in air quality would be expected with the midday option (with impacts likely lower for nights and weekends) and that change would be well within the region's emission budget.