SUMMARY
Red-Tinted Bus Lane Experience

Red-tinted bus lanes are defined as lanes that feature red-colored pavement to enhance the conspicuity of locations, station stops, or travel lanes in the roadway exclusively reserved for vehicles of public transit systems or multimodal facilities where public transit is the primary mode. Tinted pavement applications have been documented in North America going back to the 1990s, when the City of Portland, OR, experimented with using blue pavement treatments to identify conflict points between bicycle and automobile traffic. In 2023, the 11th edition of the U.S. Manual on Uniform Traffic Control Devices (MUTCD; FHWA 2023) included red-tinted transit lanes as an approved option. The 6th edition of the Manual of Uniform Traffic Control Devices for Canada (MUTCDC; Transportation Association of Canada 2021), released in 2021, also includes red-tinted transit lanes as an optional treatment.

Red-tinted bus lanes have been implemented in several cities, but there is relatively little documentation of impacts, operational challenges, and other information of value to entities interested in implementing red-tinted bus lanes. The focus of this synthesis is on the following topics:

• Developing an understanding of why transit agencies and jurisdictions such as cities have implemented red-tinted bus lanes
• Identifying key features of red-tinted bus lanes
• Documenting experiences, challenges, and considerations relevant to implementing, operating, enforcing, and maintaining red-tinted bus lanes
• Understanding the impacts that red-tinted bus lanes have had on transit travel time, reliability, ridership, safety, and other measures of effectiveness
• Identifying factors that contribute to the success of red-tinted bus lanes

Overview of Study Approach

The objective of TCRP Project J-07/Topic SD-07 was to document the current state of practice in the implementation and performance of red-tinted bus lanes in North America. The study process included a focused literature review; a survey of agencies and jurisdictions that have implemented, operated, enforced, or maintained red-tinted bus lanes; the development of case examples of selected agencies; and the development of this synthesis report.

Findings

Key findings of the project include those discussed in the following:

• Planning, design, and implementation
  • Several agencies implemented their first red-tinted bus lanes as pilot projects. The agencies reported that pilot projects can be useful for testing materials, designs, and implementation techniques and in building partnerships.

• • Some agencies observed that an advantage of using red-tinting treatments to distinguish bus lanes is that they do not interfere with bus maneuverability.
  • Funding is a concern across the board.
  • Some agencies have used intermittent and partial-width red-tinting designs to save on material installation and future maintenance costs. The agencies indicated that these designs have been effective in decreasing bus lane violations.
  • There are different views across agencies about the suitability of red tinting for part-time bus lanes and the red-tinting design appropriate for part-time bus lanes.
  • The method used to apply red-tinting materials can affect installation time and the quality of the resulting red-tinting treatment.
  • Some agencies have found design standards and specifications for red-tinted bus lanes to be useful in implementing red-tinted bus lanes in a consistent manner.
• Materials
  • According to the survey conducted as part of this project and described in this report, the most common red-tinting treatments currently used in North America are red methyl methacrylate (MMA), red thermoplastic, and red high-friction surface treatments (HFSTs) with color-coated glass aggregate.
  • Factors that influence an agencyʼs choice of red-tinting treatments include:

• Applying treatments in the correct season and weather conditions,
• Contractor or agency staff familiarity with a given red-tinting treatment,
• Coordination with other jurisdictions,
• Cost of implementation,
• Cost of maintenance,
• Cost of the product,
• Durability of the product,
• Effectiveness of the product,
• Environmental impacts,
• Expected lifespan of the product,
• Installer/contractor availability,
• Product availability,
• Safety benefits,
• Short-term installation issues such as odor and fumes,
• Simplicity of implementation, and
• Speed of implementation.

• • The consensus across the case examples seems to be that a red-tinting treatment ought to last at least 5 years. An exception to this could be made for pilot projects and projects in corridors with pending near-term roadway projects.
  • The survey results indicate that a number of agencies have moved away from red-paint treatments over time (except in pilot implementations). The primary reason for doing so appears to be the lack of durability of red-paint treatments. A secondary reason for moving away from red-paint treatments appears to be the relatively lengthy installation time required to apply multiple coats of paint.
  • Critical influences on the durability of a given red-tinting treatment are surface preparation and the condition of underlying pavement. Driveway density (i.e., the number of vehicles turning across the bus lane), the types of vehicles allowed in the bus lane, and bus stops also affect the durability of the treatment.
  • One agency observed that estimates of the life cycle of red-tinting treatments found in the literature turned out to be overly conservative for the agencyʼs climate and geography (i.e., the treatments lasted longer than predicted).
  • Some agencies have had inconsistent experiences related to the performance and value of specific red-tinting treatments. The inconsistencies might be the result of differences in climate, geography, material quality, application method, or bus lane usage.

• • Multiple agencies expressed concerns about the environmental impacts, toxicity, and odors of MMA. One case example metro area moved away from MMA for environmental reasons.
  • Variations in the shade of red tinting used exist across red-tinted bus lanes in North America. This does not seem to be problematic.
• Operations and enforcement
  • Some agencies do not have legal authority to enforce bus lane restrictions, so the actions they can take to reduce bus lane violations may be limited.
  • Agencies report that, while red-tinted lanes have improved enforcement, they do not completely solve enforcement challenges. Improvements like supplemental signage and strategically placed medians and curbs may be needed.
  • Agencies with red-tinted bus lanes report that red tinting supports self-enforcement, as does locating bus lanes away from curbs. Self-enforcement of bus lanes is an important goal of bus lane design and operation. Self-enforcement can reduce enforcement costs and improve safety.
  • Agencies observe that red tinting generally reduces the ambiguity about whether a bus lane violation has occurred.
• Impacts
  • All but one of the agencies and jurisdictions participating in the survey deemed their red-tinted bus lanes effective overall.
  • Several agencies that have implemented or use red-tinted bus lanes are relatively new to red-tinted bus lanes and are still building experience with different designs, materials, and implementation methods.
  • Many red-tinting projects in North America were completed too recently to have produced quantified impact and maintenance data, and the COVID-19 pandemic limited the ability of some agencies to conduct before-and-after studies.
  • Lane-usage compliance data seem to be the most readily available data for quantifying impacts of existing red-tinted bus lanes in North America.
  • Many of the agencies and jurisdictions that participated in the survey or case examples were not able to provide quantitative information about the impacts of red tinting specifically, as opposed to the impacts of bus lanes in general. Likewise, many of the agencies and jurisdictions were not able to isolate the costs of enforcing and maintaining their red-tinted bus lanes from other enforcement and maintenance costs.
  • Simplifying enforcement of bus lane restrictions (e.g., with red tinting) could be a strategy for improving bus lane performance.

Agency Guidance

Agencies that have implemented and operate red-tinted bus lanes offer the following suggestions for agencies that are considering implementing or operating red-tinted bus lanes:

• Conduct outreach to and coordination with multiple stakeholders. Use this outreach and coordination to develop partnerships.
• Unless continuous red-tinting treatments are needed in particular contexts to reduce driver confusion, maximize the effectiveness of the bus lane, or emphasize the visibility of the transit service that uses the bus lane, consider using intermittent or background red-tinting treatments to reduce costs.
• Consider using a double red-tinted bus lane design in the busiest corridors so that through buses can bypass stopped buses. This can also allow space for vehicle loading and separation from right-turning vehicles.
• Use durable red-tinting materials.

• Make decisions about red-tinting materials and designs based on their life-cycle costs. The up-front cost of some red-tinting treatments might be higher than the cost of other treatments, but their durability and visibility might be worth the higher cost.
• To reduce the cost of implementing red-tinted bus lanes, consider coordinating with other agencies and local governments in the region to negotiate price lists for red-tinting materials and pool procurements.
• Snow and parked vehicles can obscure red tinting and other pavement markings, so use signage to help manage bus lane usage.
• Develop a process for requiring utility companies and construction companies to restore red-tinting treatments damaged during their projects or contribute funding toward the repairs.
• Allowing emergency vehicles to use red-tinted lanes can be a significant selling point to get local municipalities on board with a red-tinting project. Another incentive is upgrading local signal systems as part of transit priority projects.
• Consider that, as physical infrastructure, red-tinted bus lanes can demonstrate to the public that transit is being prioritized.

Future Research Needs

Potential topics for future research about red-tinted bus lanes include the following:

• Collection of red-tinting treatment life-cycle data that reflect different climates, different operating environments, different materials, different application methods, and the effect of underlying pavement condition would be of value to agencies that are considering implementing red-tinted bus lanes or modifying their current approach to implementing red-tinted bus lanes. Such data would help agencies select and implement the treatments that are most effective for their circumstances.
• Quantified red-tinted bus lane performance data (including skid resistance and rate of wear) for different climates, operating environments, application methods, and underlying pavement conditions would be useful for agencies.
• Research could explore the environmental and health impacts of different red-tinting treatments as they pertain to manufacture, installation, usage, maintenance, and removal. Research could also document how agencies are managing potential health risks to personnel involved in installing, maintaining, and removing red-tinting treatments.
• Research could document and evaluate methods available for discouraging illegal vehicle turns from or across a bus lane (e.g., use of curbs or delineators) and that might supplement red tinting. This research should consider contraflow and bidirectional bus lanes as well as more-conventional bus lanes.
• Research could develop guidelines for maximizing the extent to which a bus lane is self-enforcing. This research could cover red-tinted bus lanes as well as bus lane placement, signage, and the role of automated enforcement. The research should account for whether a bus lane is a full-time bus lane or a part-time bus lane.
• Research could document and evaluate methods for accommodating legal vehicle movements in and out of bus lanes (e.g., use of broken-pattern red tinting) and for managing other conflict points.
• Documentation of strategies that have been effective in providing information about red-tinted bus lanes to the public and other stakeholders might be of value to agencies. The research could discuss data needs and how red tinting has been included in state-level driver education materials. It could also attempt to draw conclusions about whether efforts to achieve consistency in design across a region, state, or province have benefits.

• Research could document and evaluate strategies that agencies have used to make installation and maintenance of red-tinting treatments cheaper or more cost-effective. Different partial-width red-tinting designs and different intermittent red-tinting designs could be part of this research. The research could analyze the impacts of the lower-cost options on enforcement, safety, and transit service performance and develop guidelines for effective use of such options.
• Documentation of when and how bicyclists are accommodated in red-tinted bus lanes might be of value to agencies. The research could include the development of guidelines based on best practices.
• Research could document the criteria and guidelines that agencies are using for signing and supplemental pavement markings in red-tinted bus lanes. The research could document impacts on crash rates and transit performance.
• Research could document the conditions under which agencies choose to remove red tinting from a bus lane, bus stop, or queue jump lane.
• International experience in the use of red tinting for transit could be documented. Such research might result in recommendations for changes to North American practice.
• Additional research questions suggested by the agencies involved in this project are the following:
  • To what extent do fines for violating red-tinted bus lanes fund bus lane maintenance?
  • Does red tinting create side friction (perceived roadway narrowing) that has a traffic-calming effect?
  • Are red-tinted bus lanes more or less effective in suburban areas than in urban areas? Is there a connection between congestion or density and the need for or value of red tinting?