Parents of a teenager killed while driving last year are following up on their promise to change Arizona’s laws. 

Steve and Tana Smith convinced lawmakers to introduce a bill making drug and alcohol testing mandatory for drivers involved in serious crashes. 

The bill is in their son Joe Smith's name. 

The 18-year-old and another motorist were both killed when a semi-truck slammed into traffic on Interstate 10. 

Records showed the semi-truck driver admitted he was tired, but no drug or alcohol test was ever given.