NASHVILLE (AP) — A new study finds that traffic congestion and road deficiencies in Tennessee cost motorists in the state $5.6 billion a year.

The Washington-based transportation research group Trip conducted the study that calls for boosting investment in Tennessee roads, bridges and transit.

But Republican Gov. Bill Haslam announced Friday that he won't propose legislation this session to boost the state's gas tax for the first time since 1989.

The report finds that the increasing congestion means drivers waste more time and fuel each year.

According to the study 40 percent of major urban roads in the state are either in poor, mediocre or fair condition, and that one out of five bridges are structurally deficient or obsolete.

About 5,000 people have been killed on Tennessee's roads between 2010 and 2014.