Traffic Operations and Safety
Transportation Data Collection
The Office of Transportation regularly collects data to make informed and educated roadway safety and operations decisions. The office’s annual Traffic Safety and Operations Report provides data on traffic speeds, volumes and accidents as well as updates on recently completed and ongoing traffic safety and operations projects citywide. The Office of Transportation also collects targeted traffic speed and volume data when required for certain projects, for traffic calming-related requests, or when requested by individual citizens.
Setting Speed Limits
The Office of Transportation conducts Engineering and Traffic surveys to justify posted speed limits so police can use radar for speed enforcement purposes. These surveys take into account prevailing speeds, collision history, roadside conditions not readily apparent to the driver, residential density and pedestrian and bicycle safety. Generally, speed limits are set at the 5-mile-per-hour increment below the 85th percentile speed as determined by a radar survey.
Palo Alto Street Types
The following types of streets can be found in and around our city.
- Local: Minor roadway that provides access to adjacent properties only.
- Collector: Roadway that collects and distributes local traffic to and from arterial streets, and provides access to adjacent properties.
- Arterial: Major roadway mainly serving through traffic; takes traffic to and from expressways and freeways; provides access to adjacent properties.
- Residential Arterial: Major roadway mainly serving through traffic; takes traffic to and from expressways and freeways; provides access to adjacent (primarily residential) properties.
- Expressway: Major roadway with limited access to adjacent properties; devoted almost exclusively to traffic movement, mainly serving through traffic.
- Freeway: Major roadway with controlled access; devoted exclusively to traffic movement, mainly of a through or regional nature.
Road Signage and Striping
Signs and striping are generally used to convey certain regulations, warning and guidance that could not otherwise be made clearly understandable. Signs are classified into four general categories.
- Regulatory signs give notice of traffic laws or regulations
- Warning signs call attention to conditions on, or adjacent to, a highway or street that are potentially hazardous to traffic operations
- Guide signs show route designations, destinations, directions, distances, etc.
- Construction signs provide notice or direction within a construction zone
Traffic Control During Construction
The Office of Transportation is responsible for reviewing traffic control plans that are used for roadway construction work performed by private contractors. Proper traffic control is required in construction areas to reduce accidents, confusion to motorists and damage to private and public property including minimizing impacts to traffic flow.
In order to minimize inconvenience to roadway users, lane closures on arterial streets within Palo Alto are generally limited to the off-peak hours between 9 a.m. and 4 p.m. Sidewalk closures are discouraged, unless there is a convenient and safe alternate path for pedestrians. Work at night is generally not allowed, due to construction noise impacts on nearby residents and hotels.
Want to learn more?
View our 2017 Traffic Safety and Operations Report(PDF, 12MB).