As marijuana use in the United States is on the rise, a growing number of drivers are getting behind the wheel high, while regulations and law enforcement agencies scramble to keep up with the danger.

Q: We have a limit for driving with alcohol in your system, and we have a limit for cannabis, but what about all the other drugs? Why don’t we have limits for them? How can an officer know when ...

While “magic mushrooms” may be decriminalized in Colorado, state transportation officials are reminding the public that it remains illegal — and dangerous — to drive while under the influence of ...