City Council Meeting
August 27, 2002
TRANSPORTATION DIVISION
STAFF REPORT
Agenda Item # F-2
City Council Meeting
August 27, 2002
Staff Report #: 02-194
REGULAR BUSINESS: City Council Approval of Improvement Measures to Increase Traffic Safety on Sand Hill Road Between Santa Cruz Avenue and Interstate 280 and Adoption of a Resolution Appropriating $45,000 from the Traffic Impact Fee Account to Fund the Implementation of These Improvements.
RECOMMENDATION
Staff recommends that the City Council:
BACKGROUND
Previous Council Action
At its meeting of October 30, 2001, the City Council reviewed the Citywide Speed Limit Survey and directed staff to investigate reducing the posted speed limit of 45 mph on Sand Hill Road to 35 mph. In Council's subsequent 2002 Project Prioritization meeting, the City Council approved the Sand Hill Road Traffic Safety Study as a priority project.
Transportation and Bicycle Commission Meeting
On June 26, 2002, staff presented the proposed improvements to increase the traffic safety on Sand Hill Road between Santa Cruz Avenue and Interstate 280 to a joint Transportation and Bicycle Commission. The joint commission recommended the staff's proposed improvements for approval by the City Council, except the reduction of the posted speed limit on Sand Hill Road from 45 mph to 40 mph.
ANALYSIS
Reduction of Posted Speed Limit of 45 mph on Sand Hill Road
As defined in Section 627 of the California Vehicle Code, the three requirements of an engineering and traffic survey to justify posted speed limits and to enforce these posted speed limits legally with the use of radar are as follows:
In addition to these three requirements, Section 627 stipulates that when conducting an engineering and traffic survey, local authorities may consider residential density and pedestrian and bicyclist safety.
Vehicle Speeds
In spring of 1999, engineering and traffic surveys were conducted on Sand Hill road between the Menlo Park city limit and Interstate 280. The critical speeds from the 1999 speed surveys, which range from 42.8 mph to 49.9, are shown below and on Attachment "B":
| Segment | Direction | Critical speed (mph) |
| Between Santa Cruz Ave. and Sharon Park Dr. | EB/WB | 42.8 |
| Between Sharon Park Drive and Monte Rosa Dr. | EB/WB | 49.9 |
| Between Monte Rosa Dr. and I-280 | EB/WB | 49.5 |
As part of its investigation of reducing the posted speed limit on portions of Sand Hill Road, staff conducted new radar speed surveys along Sand Hill Road between Sharon Park Road and Interstate 280 at the locations shown on Attachment "C". These new surveys included the following tasks:
The critical speeds from the 2002 speed surveys, which range from 44.4 mph to 51.7 mph, are shown below and on Attachment "C".
| Segment | Direction | Critical speed (mph) |
| Between Sharon Park Dr. and Branner Dr. | WB | 44.4 |
| Between Branner Dr. and Saga Lane | WB | 48.1 |
| Between Saga Lane and Interstate 280 | WB |
49.2 |
| Segment | Direction | Critical speed (mph) |
| Between Sharon Park Dr. and Branner Dr. | EB | 45.6 |
| Between Branner Dr. and Saga Lane | EB | 50.3 |
| Between Saga Lane and Interstate 280 | EB | 51.7 |
The table above shows that the critical speeds for the westbound direction (predominantly going uphill) are lower than those for the eastbound direction (predominantly going downhill). However, a comparison of the 1999 and 2002 speed surveys does not provide a clear indication about the effect of the traffic signal synchronization on traffic speeds.
Based on the critical speeds and following the Caltrans Traffic Manual for establishing posted speed limits within 5 mph below the critical speed, a posted limit of 40 mph can be justified between Sharon Park Road and Branner Drive and 45 mph between Branner Drive and Interstate 280.
Collisions
The two-year reported traffic collisions (September 30, 1999 - September, 2001) on Sand Hill Road between Santa Cruz Avenue and Interstate 280 are shown in Attachment "D". The calculated accident rate is 1.7 accidents per million vehicle miles (Acc/MVM) for the segment between Santa Cruz Avenue and Sharon Park Road. For the segment between Sharon Park Road and Interstate 280, the accident rate is 0.76 Acc/MVM. The State average accident rate for multi-lane divided arterials is 1.17 Acc/MVM.
The total number of collisions involving bicycles during the same two-year period was two between Santa Cruz Avenue and Sharon Park Road and five between Sharon Park Road and Interstate 280. Approximate locations and dates of these collisions are shown in Attachment "E".
Unusual Roadway Conditions
Along the horizontal curves and vertical curves on Sand Hill Road, staff measured the stopping sight distances to determine the safe stopping speeds. At all locations, except the vertical curve in the vicinity of Addison-Wesley, the safe stopping speeds were determined to be greater than the posted speed limit of 45 mph. At the vertical curve, in the vicinity of Addison-Wesley, staff computed the stopping sight distance to be 320 feet for both the eastbound and westbound directions. This corresponds to a safe stopping speed of 41 mph. Based on this, a posted speed limit of 40 mph can be justified on this portion of Sand Hill Road.
Menlo Park Police Department Speed Enforcement
On June 24, 2002, Transportation and Police staff met to discuss, among other issues on Sand Hill Road, the issue of reducing the 45 mph posted speed limit on Sand Hill Road to 35 mph. The Police staff indicated that the majority of motorists are currently complying with the posted speed limits on Sand Hill Road. Reducing the posted speed limit may make majority of these motorists violators of the speed laws, which should be considered in deciding whether to retain or lower the 45 mph posted speed limit. Police staff further noted that it would be difficult to enforce a 35 mph speed limit in the portion of Sand Hill Road where the current posted speed limit is 45 mph. However, Police staff would support a posted speed limit reduction to 40 mph speed.
Transportation and Bicycle Commission Recommendation
In the Joint Transportation and Bicycle commission meeting of June 26, 2002, the commissioners voted for the retention of the 45 mph posted speed limit on Sand Hill Road. The majority of the commissioners indicated that motorists speeding was not a traffic safety concern and that reducing the posted speed limit could cause additional traffic congestion.
Staff Recommendation
As indicated above, there are portions of Sand Hill Road where a posted speed limit of 40 mph can be justified, specifically the portion of Sand Hill Road between Sharon Park Road and Branner Drive and the portion of Sand Hill Road in the vicinity of Addison-Wesley. Analysis indicates the following posted speed limits are justified in the following segments of Sand Hill Road:
However, since the Caltrans Traffic Manual does not recommend speed zones of less than 0.50 mile and short transition zones, it does not appear appropriate and may be difficult to enforce alternating 40 mph and 45 mph posted speed limits on different segments of Sand Hill Road. Consequently, two options can be considered, namely: 1) Establish a posted speed limit of 40 mph from Sharon Park Road to Interstate 280; or, 2) Retain the 45 mph posted limit from Sharon Park Road to Interstate 280.
Staff recommends reducing the posted speed limit to 40 mph because the safe stopping speed at the existing vertical curve in the vicinity of Addison-Wesley is 41 mph. Thus, the 45 mph speed limit at this location might signal to motorists that at that speed, they can attain the safe stopping sight distance. In addition, as defined in Section 627 of the California Vehicle Code, bicyclist safety was considered in the staff's analysis of establishing the speed limit. In the two-year period from September 1999 to September 2001, the total number of reported collisions involving bicycles was seven between Sharon Park Road and Interstate 280, with one fatality. With Sand Hill Road being used daily by commuter and recreational bicyclists as well as approximately 33,000 motorized vehicles, potential conflicts between motorists and bicyclists are high.
Portable Speed Display Sign
In order to reduce vehicle speeds on Sand Hill Road, staff is recommending the
installation of portable speed display signs between Addison Wesley and Saga
Lane for both the eastbound and westbound directions. The segment of Sand Hill
Road between Addison Wesley and Saga Lane is where the critical speeds are the
highest.
The portable speed display sign, as shown in Attachment "F", is a small-scale version of the Menlo Police Department speed measuring display trailer. It will display the vehicles' actual speed and therefore, provide information to the motorists whether they are traveling at the speed limit or over the speed limit. The motorists may then adjust their behavior accordingly.
This device, which has been used in the cities of San Jose and Cupertino, has proven to be effective and especially useful in reducing speeds in school zones and areas where there is a downhill grade.
Bike Lane Improvements
In order to improve bicycle lanes on Sand Hill Road, staff recommends the following improvements.
Bike Lane Signs and Bike Lane Symbol Pavement Messages
The existing bike lane signs on Sand Hill Road are sized 12-inch wide and 8-inch high and are not easily visible to motorists. Staff is recommending replacing these existing signs with bigger "Bike Lane" signs (24-inch wide and 18-inch high). This will enhance motorists' awareness of the presence of bicyclists on Sand Hill Road. Currently, there are 11 existing "Bike Lane" signs that need to be replaced with bigger signs.
The existing Bike Lane symbol pavement messages are faded and need re-painting. Furthermore, staff recommends additional Bike Lane symbol pavement messages at mid-block locations.
Parking Restriction
Since there is not enough width available on Sand Hill Road to accommodate both a designated bike lane and on-street parking, bicyclists are often exposed to unsafe conditions when vehicles are parked in the bike lane. Bicyclists are forced to merge into high-speed traffic in the travel lane. Consequently, it is recommended to eliminate on-street parking on Sand Hill Road between Santa Cruz Avenue and Interstate 280 for both eastbound and westbound directions. Due to low on-street parking demand and adequate availability of off-street parking facilities, the elimination of on-street parking along this corridor will not have an adverse effect on the parking needs of the businesses on Sand Hill Road. To indicate the parking restrictions, No Parking signs will be posted every 400 feet.
Painted Median
In addition to the above bike lane improvements, staff recommends a 3-foot wide median be painted with a non-skid material to visually separate the bicycle lane from the travel lane. Attachment G and H show the existing cross section and the proposed cross section with a 3-foot painted median, respectively. Prior to the actual implementation of the painted median, the Transportation and Bicycle Commissions and staff recommend that this be tested in a limited stretch of Sand Hill Road for trial period of at least six months. The test period will provide the commissions and staff necessary data to evaluate safety and effectiveness of this design. Upon successful trial as determined by the commissions and staff, staff will bring back this item to the City Council for approval of the actual implementation of the painted median on Sand Hill Road.
Alternative Intersection Design
Making left-turn movements at intersections is a special challenge that is faced by cyclists on Sand-Hill Road. Generally, there are two options for cyclists to make left-turn movements at intersections in the existing conditions (see Attachment I for a typical intersection design on Sand Hill Road). The first option, which is called the direct left-turn, is to use the left-turn lane by merging with the moving traffic to cross two traffic lanes, get in the left-turn lane and make the left-turn with the motorists' left-turn signal. The second option is to cross the intersection using the pedestrian green signals (indirect left-turn). This requires cyclists to come to a complete stop at the far right corner of the intersection, dismount from the bike, push the pedestrian button and wait for the pedestrians' green phase. While the second option is often considered slow and inconvenient, the first option can be overwhelming and even dangerous due to high traffic volumes and speeds, especially for inexperienced cyclists. This problem is worsened by hilly terrain and the wide intersections, which make them more difficult to cross.
In order to improve bicycle left-turn movements at Intersections, staff recommends an alternative design as shown in the Attachment J. The proposed design improves the indirect left-turn movements by making it unnecessary for cyclists to dismount from their bikes and push the pedestrian button. The low-cost design, which is widely used in western European countries and proven to be effective, only requires the installation of a bike detection loop with additional minor striping and signing within the intersection.
To make a left turn at an intersection equipped with the alternative design, cyclists go to the far right corner of the intersection (Movement 1 in Attachment J) to the designated waiting area where a bike detection loop is located. When the loop detects a cyclist, the signal controller will assign a green phase for the cyclist to cross the rest of the intersection (Movement 2). The waiting area in the far right corner of the intersection is in conflict with right-turning vehicles during the red phase out of the side streets. To avoid this conflict, right-turning movements need to be prohibited by installing a regulatory sign saying "No Right Turn on Red when Cyclists are Present". Since the designated waiting area is located between the through bike lane and the pedestrian crosswalk, the left-turning cyclists will not be in conflict with cyclists that are going straight or with pedestrians. The signage and arrow markings on the pavement will guide cyclists on how to proceed safely through the intersection.
Since the alternative left-turn design is not a standard feature in the Caltrans' Highway Design Manual, the City would not have design immunity if such a design concept was implemented. California Traffic Control Devices Committee (CTCDC), in consultation with local authorities, is the agency that adopts uniform standards for all traffic control devices to be used on California streets and highways.
Consequently, staff will obtain approval from the CTCDC to proceed
with a pilot project for this alternative design. A pilot project would assist
the City and CTCDC in assessing the safety and effectiveness of the new design.
Pilot projects typically last between six months and two years. Upon obtaining
approval from CTCDC to proceed with the pilot project, staff will bring back
this item to the City Council for approval of implementation of the pilot project.
For the purpose of the pilot project, staff recommends installation of this
alternative left-turn design at two locations: 1) Sand Hill Road and Saga Lane
to accommodate the westbound left-turning cyclists and 2) Sand Hill Road and
Sharon Park Drive/Hewlett Foundation Building driveway to accommodate eastbound
left-turning cyclists. These two locations are considered appropriate for the
pilot project due to relatively high left-turning bicycle traffic and low volume
of right-turning motorists that might be in conflict with the left-turning cyclists.
Upon successful completion of the pilot project, staff will bring back this item to the City Council for approval of actual implementation of this design alternative at the locations included in the pilot project. The staff will also identify additional locations on Sand Hill Road appropriate for this design alternative.
IMPACT ON CITY RESOURCES
The total cost to implement improvement measures to increase traffic safety on Sand Hill Road between Santa Cruz Avenue and Interstate 280 is estimated to be $45,000, which can be funded from the Traffic Impact Fee account. This cost includes staff time of approximately 110 hours needed to prepare conceptual and detail drawings, create work orders and arrange a bidding process to hire a contractor to implement these measures.
POLICY ISSUES
This project is in line with several policies in the 1994 General Plan Circulation and Transportation Element. These policies seek to maintain a circulation system using the Roadway Classification System that will provide for the safe and efficient movement of people and goods throughout Menlo Park for residential and commercial purposes, promote the use of alternatives to the single occupant automobile, and the safe use of bicycles as a commute alternative and for recreation.
ENVIRONMENTAL REVIEW
The proposed project is categorically exempt under Class 1 of
the current California Environmental Quality Act Guidelines.
| Rene C. Baile Transportation Engineer Co-Author |
Jamal Rahimi Transportation Manager |
Dino Teddyputra
Transportation Planner
Co-Author
PUBLIC NOTICE: Public Notification was achieved by posting the agenda,
with this agenda item being listed, at least 72 hours prior to the meeting.
ATTACHMENTS:
A. Resolution
B. 1999 Sand Hill Road Speed Surveys
C. 2002 Sand Hill Road Speed Surveys
D. Two-Year Collision History on Sand Hill Road
E. Two-Year Traffic Collisions Involving Bicycles
F. Dynamic Speed Monitoring Display
G. Existing Cross Section
H. Proposed Cross Section with Painted Median
I. Existing Condition - Intersection
J. Alternative Design