The Cygolite Hotshot has user-adjustable modes. I have one set for MUP use, I have it set extremely dim. When I get to the road, I hit the "mode" button once and it switches over to a super-bright flash mode I have set up. You can set brightness and flash speed.
It does not use AA or AAA batteries. Instead it has a built in rechargeable. Beam is pretty narrow, but it can get really bright.