BISMARCK, N.D. (AP) _ North Dakota's oil boom has caused traffic congestion in the western part of the state, but it's also brought in more money for the state Transportation Department.
Vehicle registrations in North Dakota have added more than $2.5 million to the state treasury.
The Legislature last year tightened requirements for getting state drivers' licenses and vehicle registrations when people move to North Dakota to work. State officials say it's difficult to know exactly how many people have moved to North Dakota to get jobs, but the Transportation Department is working to see that those people are legally licensed to drive in the state.
Linda Butts of the Transportation Department says more than 8,800 temporary vehicle registration have been issued since July 2011.