Bicycle Safety Guide and Countermeasure Selection System


Back-in Diagonal Parking with Bike Lanes

Vancouver, Washington

Prepared by Todd Boulanger, with contributions from Ali Goudarz Eghtedari and John Manix


McLoughlin Boulevard, a minor arterial in Vancouver, Washington, was no longer serving the surrounding land uses and users well. Along segments, the arterial was wider than its traffic volume necessitated, especially in the area of Clark College. The segments under study had one to two wide lanes in either direction and often no parking or parking limited to parallel stalls (see Image 1). The presence of on-street parking can positively or negatively affect the safety of bicyclists along the roadway. To provide new parking spaces while maintaining safety for bicyclists, Vancouver considered back-in diagonal parking. This design offers clear sightlines when pulling out and removes the risk that is present with parallel parking (a motorist opening the car door into the path of a bicyclist).

Four lane configuration before back-in parking.

Image 1: Four lane configuration before back-in parking.

Diagonal parking in the city up to the point of this demonstration project was laid out conventionally to allow drivers to enter 45-degree stalls head-in along some of the wider arterials. Complaints about conventional diagonal parking focused on the restricted line of sight parkers had when leaving a stall and the insecurity of bicyclists in cycling along zones with conventional diagonal parking. Research conducted by the city in the 1970s documented the risk of vehicle-to-vehicle collisions when using head-in diagonal parking on an arterial street; to mitigate this concern, city engineers separated diagonal parking lanes from travel lanes with a 12-ft buffer lane for vehicle queuing (see Image 2).

The McLoughlin Boulevard corridor also lacked bike lanes, causing some bicyclists to ride on the sidewalk rather than on the street (Image 3). However, adding bicycle lanes to the head-in diagonal parking facilities with buffer zone presented a safety challenge.

In the proposed treatment section, McLoughlin Boulevard:

Traditional diagonal parking with 12-foot buffer lane, no bike lanes and incomplete sidewalks

Image 2: Traditional diagonal parking with 12-foot buffer lane, no bike lanes and incomplete sidewalks (one block east of back-in zone).

In a zone to the east of the demonstration area, McLoughlin Boulevard has head-in diagonal parking with a 12-foot buffer lane (shown in Image 2).

This demonstration project had three objectives, which were to assess:

  1. Whether back-in diagonal parking would function as well as head-in diagonal parking with regard to safety and community acceptance.
  2. Whether back-in diagonal parking would allow bike lanes to replace vehicle buffer lanes for motorist maneuvering space, thereby improving bicyclist access.
  3. If the narrower street cross-section devoted to motor vehicle travel would lower the 85th percentile speeds.

Bicyclist access before bike lanes.

Image 3: Bicyclist access before bike lanes.

Initial treatment sites along McLoughlin Boulevard were selected during a Neighborhood Traffic Management planning process in 1999-2000. The initial parking concept proposal languished until a facility plan for a public swimming pool proposed tearing down a heritage house for parking lot expansion in Hough. Community support for back-in diagonal parking grew because it would allow neighborhood associations to improve the surrounding parking supply while providing bicycle access to surrounding public facilities and protecting existing housing stock. The site of the demonstration was relocated one half-mile east of the original site, after a request by the Parks and Recreation Department for more parking for a second pool guaranteed funding for the striping demonstration project. Additionally, engineering staff considered the new site to be less politically risky for a long evaluation period, as it had a greater supply of off-street parking, which would allow drivers uncomfortable with back-in parking access to other parking options.


The demonstration project relied primarily on new bike lane striping, stenciling and signs to create back-in, diagonal parking stalls along a zone that did not have pre-existing parking. The pre-project lane configuration generally was four lanes with a striped center line for a 61-foot-wide street (shown in Image 1) classified as a minor arterial with 7,000 vehicles per day. The post-project lane configuration added separate lanes for parking and bike lanes while removing one lane in each travel direction (see Image 4 and Table 1).

Table showing the widths of different lanes, pre- and post-project.

Two-lane road with back-in parking on one side and parallel parking on the other side.

Image 4: After conversiontwo-lane configuration with back-in parking on one side.

Support for the demonstration project was developed through repeated dialog with surrounding neighborhood associations and large institutional property owners, and then waiting for them to request project initiation at a later date. The bicycle community had guarded support for the project, as it provided one-half mile of additional bike lanes in an area with many residences and civic facilities (two swimming pools, a college, a high school, and a recreational center). Outreach to other stakeholders (elderly recreation facility clients, students, bicyclists, transit riders, pedestrians, and motorists) was accomplished by posting information on the city website; holding neighborhood newsletter discussions and a televised council session; and the posting of flyers on windshields, bus stops, and sidewalk A-boards along the project area. Final institutional support for the project was found after the transportation manager visited Seattle and observed back-in parking in use. The project then advanced to City Council for final, though guarded, approval.

Evaluation and Results

This demonstration project was evaluated using video analysis of motor vehicle interaction with parking (30 hours over six weekdays while college was in session), observational studies, feedback from users, review of collision rates and speed surveys, and review of citizen complaint files.

Motorist behavior

Driver backing into stall.

Image 5:Driver backing into stall.

Bicyclist's view along back-in parking zone.

Image 7: Bicyclist's view along back-in parking zone.

Bicycle-Motorist Conflicts

Bicycle Traffic Flows

Lane Configuration Effect on Speeds

The secondary objective of adding bike lanes and parking lanes was to reduce traffic speeds along the corridor. Vehicle speeds along this section of McLoughlin Boulevard were historically higher than the posted speed limit and neighborhood leaders, pedestrians, and bicyclists expressed concern about this problem during the Neighborhood Traffic Management planning process.

Post-project travel speeds were not reduced. They increased slightly (see Table 2). There is a visual break between the section west of the project area, which is a much more pedestrian-scaled, shared-use neighborhood. The project area, by contrast, is bordered by open-space land uses (sports fields) with few driveways and long blocks. In the next phase, enhanced pedestrian crossings with calming measures will be implemented.

Eighty-Fifth Percentile Speed Pre- and Post-Project.

Collision History

Conclusions and Recommendations

Based on the results of the analysis, the city decided to extend back-in angled parking with a bike lane to other segments of McLouglin Boulevard, as well as use back-in parking in other locations throughout Vancouver.

Recommendations for future Vancouver projects included the following:

  1. Widen the standard parking stalls from 9 feet to 9.5 feet or provide other stall position guidance such as raised markers.
  2. Adopt a supplemental back-in parking sign.
  3. Adjust the striping layout to add turn lane for west bound traffic into western entrance of parking lot (site specific).

Simulation before back-in parking.

Image 9: Simulation before back-in parking.

Overall, this treatment has been very effective at balancing bicyclist access (an increase in trips) while providing for growing parking demand. The adoption of recommendations #1 and #2 has met resistance from city maintenance crews ("another sign to stock" and "if the drivers need the pavement markers, then there must be a problem with this type of parking"). The proposed projects will be using the wider stall (9.5 feet).

The use of photo simulations of the planned parking scenario was very helpful during the staff and public process stages, as few if any stakeholders had experienced this type of parking before or remembered doing so while visiting Seattle in the past (Images 9 and 10). This type of parking demanded a lot of public discussion, more so than any other striping project, especially since parking was being added rather than removed. It is ideal for a stakeholder group (business, engineers, residents, etc.) to visit a city with this type of parking before adopting it on a district-wide basis.

Simulation after back-in parking.

Image 10: Simulation after back-in parking.

Vancouver plans to adopt the back-in form of diagonal parking along wider arterials where bike lanes are desirable and the surrounding land uses support pedestrian trips and shared uses. The use of conventional diagonal parking with bike lanes is no longer acceptable. Where bike lanes are required and back-in parking is not adopted because of low resident and business support, parallel parking is indicated. Back-in parking with bike lanes might be thought of as a kind of road diet, plus having parking and bike lanes but still keeping a narrower cross section to constrain car traffic.

Costs and Funding

An original budget of $5,520 for signs, striping and traffic control was established. This cost was split between the Transportation Services and the Parks and Recreation departments (the parking was located in front of their recreation facilities and at their request). At the time of the project, the City was in the process of applying for Community Development Block Grant federal funds for the second portion of $100,000 to fund pedestrian crossings. These funds were added to $80,000 allocated for the striping and refuge islands.


Ali Eghtedari, PE
Traffic Engineering & Operations
City of Vancouver