The No. 1 contributor to serious crashes in Utah is speed. Most fatalities happen on roads where motorists drive faster. Here are Utah's roadways with the most fatalities:

No. 1. — I-15 with 44 fatalities

No. 2. — U.S. 89 with 23

No. 3. — I-80 with 18

No. 4. — U.S. 191 with 13

No. 5. — U.S. 6 with 9

No. 6. — U.S. 40 with 8