Background

Speeding is a major factor in motor vehicle crashes on local roads, 

arterials, and freeways. Exceeding the posted speed limit or driving too 

fast for conditions contributes to more than 30 percent of all highway 

fatalities in the United States annually. Setting appropriate speed limits is 

an essential element of highway safety. A rationally determined speed 

limit is one that is safe, considered appropriate by most drivers, and 

enforceable. USLIMITS2 provides a fact-based set of decision rules to 

determine an appropriate speed limit for a specific roadway segment. 

USLIMITS2 is a user-friendly and logical web-based tool designed to 

help practitioners set credible, consistent, and enforceable speed 

limits. USLIMITS2 is applicable to all types of roads ranging from local 

roads and residential streets to freeways. The tool’s accessibility and 

broad applicability make it an important resource in any transportation 

practitioner’s toolbox.

How Does USLIMITS2 Work?

Using the basic information entered by the user, USLIMITS2 runs proven 

algorithms to develop a recommended speed limit. Inputs include:

•	 Type of surrounding development (e.g., rural, fully developed);

•	 Access points (e.g., the number of driveways, intersections, and traffic signals);

•	 Road function/area type;

•	 Road characteristics (e.g., divided or undivided, number of lanes, annual average

daily traffic (AADT), roadside hazards, and section length);

•	 Freeway characteristics (e.g., number of interchanges, section length, and AADT);

•	 Existing vehicle operating speeds (50th and 85th percentile);

•	 Pedestrian activity;

•	 Crash history; and

•	 Special conditions (e.g., adverse alignment, transition zones, and parking).

USLIMITS2

A Web-Based Tool for Setting Appropriate Speed Limits

New Featur

Enha

•	 New Look – Pages have been updated

to provide a simple, clean look.

•	 Help – A help link on each page points

back to the User Guide, documentation

on the decision rules, and other useful

information.

•	 Local Storage – Users now have full

control over where projects are saved.

•	 No Account or Log-In Needed –

Project files can now easily be shared

with co-workers and decisionmakers

without having to reveal user names

and passwords.

•	 Crash Data – USLIMITS2 can work with

total crashes or only injury crashes.

•	 Additional Choice for Route Type –

Users can select “one way” streets

as an option for road sections in fully

developed areas.

•	 Updated Reports – Reports now

include start and end locations

for speed zones and other project

information.
USLIMITS2 in Actio

As shown below, users from Federal, State, and local governments; law 

enforcement; universities and non-profits; and the private sector have 

worked on over 3,000 projects with the USLIMITS2 tool. For example, in 

Maryland USLIMITS2 has been used to evaluate existing speed limits on 

major urban freeways. 

Begin a New Project Now

Access the USLIMITS2 web-based tool now at:

http://safety.fhwa.dot.gov/uslimits/.

Click on “Create a New Project” to start a new project file. You can revise 

or update an existing project later by uploading your saved project file. 

Please read through the User Guide before starting a new project and 

contact help@uslimits.org for technical assistance.

Upon request, FHWA provides training to State and local agencies on the 

USLIMITS2 application. Please make a training request via

help@uslimits.org.

The Bene

USLIMITS2

•	 Encourages consistent speed

limits for specific road and

traffic characteristics;

•	 Improves the consistency

of speed limits within and

between States;

•	 Supports motorists’

acceptance of and compliance

with speed limits;

•	 May reduce speed differences

within the traffic stream,

potentially leading to fewer

crashes;

•	 Increases transparency of the

methods used to determine

speed limits;

•	 Helps in responding to public

and political concerns; and

•	 Supports the integrity of speed

enforcement and adjudication.

For More infor

http://safety.fhwa.dot.gov/uslimits/

Guan Xu

FHWA, Office of Safety

guan.xu@dot.gov

(202) 366-5892

FHWA-SA-13-001

Any Practitioner Can Use

USLIMITS2 is of particular benefit to local communities and agencies without ready 

access to engineers experienced in conducting speed studies for setting appropriate 

speed limits.

For experienced engineers, USLIMITS2 can provide an objective recommendation, 

validating engineering decisions associated with determining and setting speed limits.

5% Federal Government

29%

State Government

31%

Local Government

18%

Consultant

Other 8%

2%

Law Enforcement

7%

University/

Non-Profit