A study by the University of North Carolina at Charlotte shows the Tar Heel state has some of the most congested roads in the country.

The report shows motorists in California, Minnesota, New Jersey and North Carolina has some of the worst traffic in the United States.

The study based on data from 1984 to 2005 shows road conditions have improved in recent years, but congestion and traffic deaths have increased.

Lead author David Hartgen says states need to focus on transportation projects to reduce congestion.

North Dakota and South Carolina rated highest in cost efficiency.