City of Los Altos

Traffic Calming and Bicycle/Pedestrian Safety Toolkit

April 2010

Table of Contents

Purpose

Selection of Traffic Calming and Bicycle/Pedestrian Safety Measures

Traffic Calming Measures and Devices

Bicycle and Pedestrian Safety Measures

Glossary

References

End Notes

Appendix

The purpose of this toolkit is to document and describe the traffic calming and bicycle/pedestrian measures that are currently approved by the City of Los Altos on Los Altos streets. The intention is to provide a high level overview of approved tools for use in Neighborhood Traffic Management Programs (NTMPs) and other traffic related projects.  With input from residents, city staff can assemble these tools into effective solutions that meet residents' needs.

Traffic calming and bicycle/pedestrian measures can result in the following benefits for Los Altos residents:

Selection of Traffic Calming and Bicycle/Pedestrian Safety Measures

The toolkit includes a variety of devices and measures that change the physical environment. Each situation is different and selected measures must be appropriate for that specific location or neighborhood.  Before committing to any type of measure in response to a resident or neighborhood request, city staff will research the issue and quantify the problem through data collection and observation. All factors and conditions that may be contributing to the problem need to be reviewed and evaluated before any type of measure can be recommended.

The primary purpose of traffic calming in Los Altos is to reduce speeds city-wide. Another desired goal is to reduce the volume of traffic on local (residential) streets.  Volume reduction measures must typically be applied to an entire residential neighborhood; spot treatments on one local street to significantly reduce volume for only that street is often unachievable, as there can not be a significant, negative impact on other local streets in the general vicinity. A thorough and exhaustive traffic study of the surrounding neighborhood is typically needed when addressing traffic volume.

The issues, advantages, and disadvantages associated with each device or combination of devices help identify the most appropriate and acceptable device(s) to address a traffic problem. The following are desired objectives when choosing a device:

• Addresses the problem in the most efficient and cost effective way possible
• Minimizes impact on adjacent streets
  
• Is consistent with neighborhood character
• Preserves Fire and Emergency Medical response criteria
• Addresses bicycle and pedestrian safety
• Addresses safety issues related to nearby schools
• Accommodates the dimensions of the street (Ex., a traffic circle can only be built in an intersection that is large enough for it; maintain minimum travel lane widths)
• Follows the guidelines of the Manual on Uniform Traffic Control Devices (MUTCD)
• Is consistent with Caltrans Design Guidelines
  

In addition, the attributes of Los Altos local streets must be taken into account when selecting measures, such as lack of sidewalks and bicycle lanes and minimum street lighting.

Sometimes, the most effective traffic management programs use a variety of traffic tools as many of the devices complement each other. For instance, speed humps and chokers can be used effectively together, as can mini-traffic circles and curb extensions. Center median islands and chokers are often installed as a set. Raised crosswalks and curb extensions work well together. Many other combinations of traffic management devices can be effective.

Traffic calming measures and devices fall under one of the following three "E" categories:

Education (Informational)

Educational measures and devices are intended to increase driver's awareness of surroundings and influence driver behavior without physical changes to the roadway. Examples of educational measures and devices include neighborhood traffic safety campaigns, radar speed display units, sign installation, and pavement marking changes. Because these measures are not self-enforcing, they can have limited effectiveness and usually need to be supplemented with other traffic calming measures.

Enforcement

Targeted police enforcement is intended to influence driver behavior without physical changes to the roadway.  Because the police typically have limited resources, targeted enforcement is often not a long term solution and needs to be supplemented with self-enforcing devices.

Engineering

Engineering measures are self-enforcing devices installed on roadways to influence driver behavior.  These self-enforcing devices can further be classified by the desired result one hopes to achieve. 

• Devices whose primary purpose is to slow traffic speed and address safety concerns and quality of life include roadway narrowings such as chokers and bulb-outs, vertical deflections such as speed humps and raised crosswalks, and horizontal deflections such as chicanes, mini-traffic circles and modern roundabouts.  These devices may be appropriate for both local and collector streets.
• Devices whose primary purpose is to reduce traffic volumes on local streets and discourage cut-through traffic from using residential streets. Devices include median barriers and forced turn lanes.  The objective is not to push the problem over to another residential street but to divert drivers to use collector and arterials instead of residential streets as cut-through streets.  By their nature, these devices are used on local, residential streets.

The traffic calming devices and measures described in this toolkit are listed in the tables below by the issue they address:

• Speeding
• Traffic volume on local (residential) streets
• Vehicle collisions

• Low (less than $10K)
• Medium ($10K-$50K)
  
• High (over $50K)

Table 1: Speeding

Table 2: Traffic Volume on Local Streets

Table 3: Vehicle Collisions

Pedestrian Safety and Sidewalks

Bicycle Safety and Bikeways

[11] ITE Traffic Calming Definition