The Mike O'Callaghan - Pat Tillman Memorial Bridge not only allows you to avoid the traffic, it's a great place to get out and walk and get the best view of the Hoover Dam. Easily the best vista point for getting a picture of it without having to rent a helicopter.
There's a small parking lot for people who wish to walk on the pedestrian path. I warn you, parking can be competitive, and there's no parking allowed on the highway if the lot is full.
There are no fees to park, and there's no admission price to go up and walk on the bridge.
You can get up to the bridge by either stairs or a really long ramp that isn't steep to climb.
The pedestrian walkway on the bridge is about 5 feet wide. Since it's been raining off-and-on for a few days, it was a little slippery in parts.
The railing along the edge is a little lower than shoulder-high with no fence blocking your view or photo ops. There's a thick concrete barrier separating you from the high speed traffic. When a big truck goes over the bridge, it feels like a mini earthquake.
My mom and I trekked all the way to the end of the pedestrian walkway on the Arizona side and touched the wall before heading back with no problem, and she usually has trouble with long distances. Our walk from the car and back was a little over half a mile.
It was pretty cold and windy on the bridge. Dress warmly.