The United States Department of Transportation (USDOT) or ”DOT” as it’s more commonly referred to, is one of the executive departments of the federal government agency that is responsible for overseeing and regulating the country’s transportation systems and infrastructure.

Founded in 1966, the DOT’s mission is to “ensure a fast, safe, efficient, accessible, and convenient transportation system that meets our vital national interests and enhances the quality of life of the American people.”

Headquartered in DC, the organizations within the DOT include the Federal Highway Administration, the Federal Aviation Administration, the National Highway Traffic Safety Administration, the Federal Transit Administration, the Federal Railroad Administration, and the Maritime Administration. Each state also has its own DOT, which handles local transportation projects, road maintenance, vehicle registration, and driver's licensing.

What is the DOT responsible for?

The DOT sets and enforces policies, safety regulations, and funding related to: highways and roads, railways and transit systems, air travel and aviation safety (through FAA), maritime transportation (through MARAD), commercial trucking (through FMCSA), pedestrian and bicycle safety, and accessibility in transportation.

The DOT employs over 55,000 people with various expertise and skillsets. These include (but are not limited to) engineers, administrators, field inspectors, and policymakers. Positions are available at both the federal and state level. Here’s a breakdown of who works for the DOT and what they typically do. While this list of roles is not exhaustive, it provides a broad overview of the responsibilities that are intricately assigned to ensure the conditions in which we drive, fly, and sail are as safe as possible. 

- Transportation Planners: develop strategies for infrastructure development, transit systems, and traffic management

- Policy Analysts: research and shape regulations, safety laws, and federal transportation policies

- Civil Engineers: design and oversee construction of roads, bridges, and highways

- Traffic Engineers: analyze traffic patterns and help improve flow and safety

- Mechanical/Electrical Engineers: work on transit systems, vehicle standards, and more

- Surveyors: measure and map land for construction projects

- Inspectors: check commercial vehicles, road conditions, and construction sites for compliance with DOT standards

- Enforcement Officers: enforce transportation safety regulations (especially under FMCSA which focuses on commercial vehicles/trucking and the NHTSA which focuses on highway traffic safety)

- Hazmat Specialists: regulate and monitor the transport of hazardous materials

- IT Specialists: maintain traffic systems, GPS infrastructure, and DOT websites

- Project Managers: oversee transportation projects and federal grant programs

- Procurement & Budget Analysts: handle contracts, budgets, and federal/state funding

- Lawyers: work on transportation laws, contracts, and litigation

When will you need to interact with the DOT?

While the average driver may not have to interact directly with the DOT, the department is responsible for setting the guidelines for many processes related to vehicle ownership and maintenance. For example, what’s required to pass a driver’s license and register a vehicle. If you drive a vehicle for work (e.g. delivery trucks, freight, or passenger vans) you may need a DOT medical exam and to comply with DOT hours-of-service rules. You may also need to get DOT drug/alcohol testing, which is required for those with a Commercial Driver’s License (CDL).

Checking your tire size or DOT number

Most drivers will have their first interaction with “DOT” terminology when checking the size of their tires or other information contained within the DOT number on the sidewall of their tire. The first three characters of this number are actually letters. It should always start with DOT, meaning that they’ve passed the safety standards of the Department of Transportation. To read more about what information is included in a DOT number, read our previous blog What Do DOT Numbers Mean? Needless to say, if your tire does not have a DOT number, it may not be safe or legal to drive in the US. If you need help locating the DOT number on your tires, watch this video below.

To find out more about tire sizes, read our previous blog article:

How Do Tire Sizes Work?

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