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February 20, 2001
Mr. Thomas G. Gatzunis. PE
Director of Community Development
19 Moore Street
Belmont, MA 02178-9156

RE: Review of the Concord Avenue Bike Lane

Dear Mr. Gatzunis;

At your request, The BSC Group has conducted a review of traffic engineering issues related to the newly designated bike lanes on Concord Avenue between the Brighton Street/Blanchard Road intersection at the Cambridge city line and Common Street in Belmont Center. This letter report summarizes our review of the first phase of work, which includes a review of the existing conditions on Concord Avenue, with particular attention focused on existing pavement striping and lane utilization, and the memo from Belmont Bikeway Planning Committee entitled "Bike Lane Improvements Suggestions, Concord Avenue". Based on this review we present recommendations for near-term actions to address identified safety issues.

Existing Conditions

Concord Avenue, from Blanchard Road to Common Street is a four-lane divided minor arterial roadway connecting the town center of Belmont to the city of Cambridge. Several streets intersect Concord Avenue to form T-intersections, with median openings at most of these intersections to accommodate turning traffic. A pedestrian-actuated signal is located near the Belmont High School at the Concord Avenue/Cottage Avenue intersection.

The roadway cross section in both directions consists of: a curbside parking lane, a bike lane, and a vehicle travel lane as shown in Figure 1. The parking lane width varies from 8.5 feet to over 10 feet. Next to the parking lane is the bike lane delineated with pavement markings with an average width of 4.5 feet. There are currently no signs used in conjunction with the bike lanes. The remaining roadway pavement serves as the travel way for vehicles. Without intending to, the current pavement striping on Concord Avenue has resulted in sub-standard travel lane widths for vehicles at certain locations. For example, the travel lane on Concord Avenue eastbound from Bright Road to Blanchard Road is less than 10 feet wide with a 1.5 foot offset from the curb.

At major intersections, left turning vehicles from Concord Avenue seeking adequate gaps in the opposing traffic are often delayed as is the through traffic that has no room to pass the left turning vehicles. This occurs frequently at Concord Avenue westbound at Bright Road where vehicles park along the curb at the intersection. Eastbound vehicles making a U-turn near the First Church in the vicinity of the Post Office do not have enough room to make the U-turn and often have to reverse direction before being able to complete the U-turn. The bike lane terminates at Common Road at the railroad bridge without any advance warning to motorists and bicyclists. Bicyclists have to merge with vehicles at this point which can cause a safety problem.

Design Guidelines Roadway Cross Sections

The MassHighway 1999 edition of Building Better Bicycling, which incorporated the 1999 AASHTO Guide for the Development of Bicycle Facilities, presents guidelines for implementing improved bicycle conditions on roadways. The Manual on Uniform Traffic Control Devices (MUTCD) 2000 edition also provides information on signing and pavement markings for bicycle facilities.

Figure 1 shows a proposed typical bike lane cross-section. A minimum width of 5 feet is recommended for a bike lane adjacent to a parking lane. The recommended width for a parking lane is 8 feet. The rest of the pavement is the travel lane. Given the available roadway cross section on Concord Avenue, the minimum travel lane width should be 11 feet with, a one-foot offset.

Signing and Pavement Markings

Currently there is no signing for bike lanes on Concord Avenue. The 11/20/00 memo from the Belmont Bikeway Planning Committee ask for clarification of intent to motorists and bicyclist. Such clarification can be made through the provision of signing and pavement markings. We recommend the installation of "Bike Lane Ahead" (R3-16) and "Bike Lane Ends" (R3-16a) signs at the beginning and the end of the bike lanes respectively. According to the MUTCD 2000. these signs should be installed in conjunction with the Bicycle Lane Symbol pavement marking

To alert bicyclists to the fact that the bicycle lane is ending, we recommend the use of dotted lane lines for the last 100 feet of the bike lane. Motorists also need to be warned to watch for bicyclists, and the MUTCD recommends that the "Share the Road" (W16-1) sign be used in conjunction with the "Bicycle Crossing- (W11-1) sign. These should be installed about 100 feet in advance of the end of the bike lane on Concord Avenue. In the vicinity of bus stops, solid bicycle lanes should be replaced with dotted lane lines "Bike Route" signs (011-1) should also be installed at every quarter mile along the corridor and in the vicinity of major intersections.

It was observed in the field and also contained in the memo that vehicles waiting to make a left turn from Concord Avenue often blocked through traffic. We recommend that at those locations, a left turning storage lane or a wide travel lane (18 feet minimum) be provided if possible. Figure 2 shows a typical intersection layout and Figure 3 shows an intersection layout with a left turning storage lane. This could result in the loss of on-street parking spaces. Locations where left turn lanes may be required include Bright Road, Cottage Road and Goden Street. An alternative accommodation for left turn storage would be to widen the roadway at the intersection. This could be achieved by removing parts of the existing median. Parking spaces may be preserved under this option which should be considered under the long term improvements to Concord Avenue.

The current straight alignment of the parking lane encourages some motorists to use it as another travel lane. This issue should be addressed in the long term by creating neckdowns or curb extensions along the corridor to interrupt the straight parking lane alignment. In the short term we recommend the installation of the traffic sign R3-17a. This sign may be used also notify bicyclists that they may encounter parked vehicles

Please feel free to contact us with any questions regarding information contained in this letter report.



Sam Offei-Addo, PE Project Manager

Charles A. Kalauskas, PE Senior Vice President