If you drive past a highway construction project and notice that workers aren't wearing safety vests, hardhats or other personal protective equipment, it's probably because their employers do not require or enforce PPE use, according to a survey of road construction safety leaders.

Slack promotion of PPE by employers is the number one barrier to using safety gear, according to research sponsored by the International Safety Equipment Association.

High-visibility safety vests and hardhats are the most commonly used types of PPE, worn when needed about 75 percent of the time, according to survey respondents.

Earplugs/muffs and eye protection are worn only about half the time when needed, and usage rates for respiratory protection, coveralls, and face shields fall well below that level - in the 30 percent to 40 percent range.

Between six and seven out of ten workers wear fall protection, gloves and protective footwear when needed, said respondents.