Found this long but interesting discussion on a web search:
http://www.tfhrc.gov/pubrds/julaug99/hoover.htm
Bypass info, seems to be here, guess you won't be going here??
http://www.hooverdambypass.org/Whats_New.htm
OOOHHH, found this one, this may be the real answer??
http://www.usbr.gov/lc/hooverdam/crossingguide.pdf
Hope this helps,
ON EDIT: Lots of answers say yes, in the time it took me to surf you an answer up! Enjoy the ride, the views are special, hope you find your mom in better shape.