Which is one of the primary responsibilities of washington's department of transportation?
to develop new forms of transportation
to reduce dependency on car use
to ensure equal access to public transportation
to manage roads, bridges, and railways

to manage roads, bridges, and railways

Explanation:

I'll explain why the other options are wrong.

- to develop new forms of transportation is wrong because Americans adopted a free market economy. Private companies tend to be the one who develop new form of transportation and introduced them to the market.

- to reduce dependency on car use is wrong because there it is what they advocated to the public, not necessarily their responsibility.  Responsibility is the things that they have to achieve. Whether you use a car or not is more of a personal choice.

- to ensure equal access to public transportation is more of a human right issue. Which means that it's the responsibility of the federal government rather than department of transportation.