By Mia L. Birk & George Hudson
Principals, Alta Planning + Design
The Springwater Corridor is a 25.7 km (16 mi) paved shared-use path from Portland’s inner eastside heading east to the adjacent suburbs of Gresham and Boring. A rail-to-trail conversion, it follows power lines and is part of a larger trail system known as the 40-Mile Loop extending throughout the Portland metropolitan area.
Currently experiencing over half a million annual users, the trail crosses 28 roadways along the way, offering an interesting case study of trail-roadway crossings. Almost all are at locations away from existing roadway intersections, thus few before and after safety or functionality comparisons can be made. However, we offer qualitative observations where appropriate.
Evaluation of trail-roadway crossings involves analysis of traffic patterns of vehicles as well as trail users. This includes traffic speeds, street width, traffic volumes (average daily traffic and peak hour), line of sight, and trail user profile (age distribution, destinations). Although many trails or paths use grade-separated crossings of major roadways whenever possible, these are expensive and must be well-designed, or they are not used. On the Springwater Corridor Trail, there are five grade-separated crossings of roadways, three of which existed before development of the trail, and the last two were installed as a new roadway improvements project after the trail was completed. Essentially, the creation of the five grade-separated crossings were therefore funded by sources other than trail construction dollars.
The existing crossings fall into the following categories:
Unprotected, marked crossing of local street.
Most of the minor public roadway crossings along the Springwater Corridor are serviced by unprotected crossings consisting of crosswalk markings and signs. Where the crossing is of a public roadway, trail users are required to stop for roadway traffic. In addition, there are several private driveway crossings of the trail. At these private driveway crossings, motorists are required to stop for trail users. These crossings have a low volume of traffic and are not public street right-of-ways. As a general policy on the Springwater Corridor Trail, private driveway users are required to stop for trail users as indicated by stop signs and marked crosswalks.
In each case, the crossing design took into consideration vehicular traffic, line of sight, trail traffic, use patterns, road type and width, and other safety issues such as nearby schools.
These crossings have the following characteristics:
No trail user and motorized vehicle conflicts have been reported. The private driveway crossings typically serve large industrial complexes, and their access across the trail is permitted by the trail managing agency (the city of Portland). There have been no issues at these private driveway crossings, and motorists do stop when crossing the trail.
Two of the three median refuge islands have landscaping. The landscaping has been subject to damage from automobiles.
The trail leads users very close to a major intersection at Southeast Linnwood and Johnson Creek Boulevard. This intersection went through a major redesign shortly after the Springwater Trail was built. New improvements included signalization of this intersection. Trail designers recognized the potential of increased safety by diverting trail users to the new signalized crossing.
In addition, the former rail line crossed an existing intersection at Southeast Bell and Johnson Creek Boulevard at a diagonal through this intersection. The intersection was signalized prior to the construction of the trail. Trail users now utilize the existing signal, crossing each street one at a time.
The crossings have the following characteristics:
Trail routed to Johnson Creek/Linwood signalized intersection. Trail users cross using crosswalks.
No collisions have been reported. Trail users complain of having to cross two crosswalks at Bell and Johnson Creek, thus requiring them to wait for two signal cycles.
There are four locations — Southeast 82nd Ave, Southeast Foster Road, Southeast 122nd Ave and Eastman Parkway — along the Springwater Corridor where the trail crosses a major roadway of above 15,000 ADT. In all four cases, the crossing width was greater than 18.3 m (60 ft), the nearest intersection more than 106.7 m (350 ft) away, and all had anticipated trail user volumes of greater than 100 per hour. Trail designers felt that new signalized crossings would be necessary to facilitate safe travel, and thus developed a signal warrant analysis that projected use through trail user numbers from the Burke Gilman Trail in Seattle, and user counts on a 1.6-km (1-mi) built portion of the Springwater Corridor in Gresham. Each location was also analyzed for sight lines, impacts on traffic progression, timing with adjacent signals, capacity, and safety.
Trail users activate the signal as follows:
At Southeast 82nd, Southeast Foster Road and Southeast 122nd Avenue, the crossing includes a median island to reduce the crossing distance, signal activation in the median for those unable to cross the entire roadway in one movement, and advance warning signs for motorists. Other crossing features follow the guidelines provided for diverting users to an existing signal as described earlier.
Signalized crossing at 82nd Ave and 122nd Ave includes: flat grade with two marked crosswalks (one for each movement) and landscaped median; pedestrian and equestrian push button activation; bicyclist loop detector signal activation; flat grade on approaches with good sight lines; advance warning signs for motorists.
The signalized crossings have been effective, safe, and functional. Since their installation in 1995, there have been no reported collisions, with an estimated 500,000 annual users. Trail users note that although they must activate the signal and wait for a green light, motorists have gotten used to the signal and frequently stop before they get the red light. Traffic engineers report minimal interference with nearby signals, given the relatively distant spacing from the nearest signalized intersections. They also report no problems.
There are five grade-separated crossings on the Springwater Corridor. These crossings consist of both over and undercrossings of roadways. Interstate 205, Highland Road/181st, and Telford Road were existing grade-separated crossings developed in response to the presence of the railroad. As such, these crossings are well integrated into the trail layout and easily used by trail users.
Hogan Road and the 7th Street Bridge, both in the City of Gresham, are roadway improvement projects built after the trail was constructed. At both these roadway crossings, the roadway goes over the trail, and Johnson Creek is immediately adjacent to the trail. The Hogan Road crossing was implemented in 1995, while the 7th Street Bridge project followed a few years later. Both grade-separated crossings were built in anticipation of high projected vehicle volumes and speed.
Key characteristics of these undercrossings include:
Hogan Road, having been the first of the two undercrossings to be implemented, had several shortcomings. Placement of the trail at the two-year flood plain elevation resulted in regular flooding and closure of the trail. With each flooding event, sediments from the creek were deposited on the trail, requiring regular clean-up. The approach to the undercrossing did not facilitate complete visibility through the undercrossing area, resulting in unsafe feelings among users along the approach. Lighting installed in the underpass area was vandalized, requiring retrofitting of the lights with metal cages. In order to meet ADA grades on the trail approach, a switch back ramp was incorporated on the eastern side of the undercrossing approach. Turning radii used on this approach tend to be a bit tight for bicyclists’ comfort. Today, about half the trail users opt to use the alternative, at grade crossing route in lieu of the Hogan Road undercrossing, regardless of creek conditions.
These lessons learned were taken to heart when the 7th Street Bridge project was proposed. Key characteristics of this undercrossing include:
These improvements resulted in an undercrossing that has been well-received and equally well-used by the public. Flooding and maintenance problems are few. Most trail users are surprised to learn the bridge came in after the trail.
Trail crossing designs tailored to the site characteristics (type of cross-street, traffic volumes, street width, traffic speeds, proximity to existing intersections, etc.) have resulted in well-functioning trail-roadway intersections with no reported safety problems to date. Experience with some under-crossings highlighted the importance of good design, including open approaches with good visibility and consideration of site environmental conditions.
Principal, Alta Planning + Design
Portland, OR 97214
3604 SE Lincoln St
1Mia Birk was formerly the Bicycle Program Manager for the City of Portland. George Hudson, previously senior designer for the Portland Parks Bureau, led the planning, design, and implementation effort for the Springwater Corridor. Ms. Birk and Mr. Hudson collaborated on intersection design along with a team of engineers.