You could charge $5.00 a mile if you can negotiate it. The IRS deductible rate is just a standard most people use. Honestly, unless you have a legit reason, charging more then the standard will just hurt the trust between you and your client and maybe lose you the job. Th purpose of the milage rate is to cover the cost of gas, vehicle maintenence, insurance, and ownership of car (basically $.44 represents the average cost to operate a vehicle over it's lifespan).
What many people do is start your billable hours from door to door if someone is more then XX minutes/miles from you. This is very acceptable.