That's the opposite of what I have observed. They tend to be very cautious and slow from what I've seen and never cause any direct danger (although a lot of them are geriatric, so maybe if you are on a motorcycle they have trouble seeing you - I don't ride, wouldn't know).

I see them cause indirect dangers all the time, since they are more concerned about their gas mileage meter saying they are helping the earth, than the intrinsic danger of a 50-car traffic jam directly caused by them doing 60 in a 70. But the sign underneath that says "minimum 45" so technically they are fine, and don't share any legal fault with the distracted driver who ultimately slams into the back of the resulting traffic jam.