Cities have two options for setting default speed limits: citywide or by street category (e.g., major, minor, alley). Citywide speed limits are generally easier to implement and may be easier for drivers to follow. However, in cities where there is clear differentiation between major arterial streets and local or minor streets, setting speed limits based on category of street can sometimes allow cities to lower speed limits on a large number of streets below what would be allowable citywide (i.e., 20 mph on minor streets vs. 25 mph citywide).

If cities have the authority to set default speed limits, they should decide whether to implement citywide limits or category limits based on what makes the most sense given the local conditions.

Applicable on all streets—major, minor, and shared streets / alleys

Category speed limits apply speed limits to specific categories of streets based on broad classes, such as major streets, minor streets, and alleys, allowing cities to set a small number of speed limits that apply to nearly all streets. This simple categorization scheme allows cities to quickly adjust speed limits on most streets, and frees up resources to focus on high-crash corridors or places where site-by-site analysis is necessary. Depending on the city, setting speed limits by category might be more politically feasible than setting a default citywide limit. If setting categories based on major and minor streets, practitioners should develop definitions for these streets that are easy to use based on existing local data.

Recommended default major streets speed limit: 25 mph
Recommended default minor streets speed limit: 20 mph
Recommended default shared streets & alleys speed limit: 10 mph