The Pennsylvania Department of Transportation (PennDOT) has released updated voluntary guidelines asking autonomous vehicle (AV) makers testing in the state to put a second safety engineer in the passenger seat, reports the Pittsburgh Tribune-Review.

The new guidelines come as part of an effort to improve safety and went into effect on Aug. 1. Secretary of Transportation, Leslie Richards, expects all companies in Pennsylvania to comply, according to the report.

Specifically, PennDOT wants self-driving vehicles being tested to have a second person in the vehicle when it is traveling faster than 25 mph. PennDOT's guidelines also give companies the option to provide just a single driver, however, that person should have additional safety training.

Also going forward, companies will be expected to complete a "Notice of Testing" which details facts about the company, the vehicles it plans to test, locations it plans to test in, and the identity of drivers, reports the Tribune-Review.

In addition, under the new guidelines, autonomous vehicle companies planning to test in Pennsylvania should submit a comprehensive safety plan as well as data such as number of miles driven and employment opportunities generated due to the testing project.

Without authorization from the state Legislature, PennDOT cannot regulate the testing of autonomous vehicles. The updated guidelines are intended to impress upon AV companies that they should take all necessary steps to ensure safety as PennDOT awaits legislative action.