The primary driver gets to decide the color, I say. If it's because of the "red cars get more tickets" myth, it's just that -- a myth/urban legend. Sure, we can all point to (or are) a red vehicle driver who's received a ticket at some point, but statistically they aren't ticketed any more than any other color. I made it 14 years in a red (Sunfire Red Pearl) 1992 Toyota Corolla without ever getting a ticket, warning, accident or any other issue on the roadways. 14 years of daily driving and only one ticket in a major metro area. I now drive a "Redfire Pearl Metallic" 2006 Ford Escape Hybrid. Seen plenty of people getting tickets (it's Fiesta time in San Antonio) and can't recall that any of them were red.
If it's something else, I revert to my original point -- if this is going to be your primary vehicle, why does it matter to her what color it is? I wouldn't have dreamed of having my husband tell me I couldn't get a certain color in the Ford Escape (my primary vehicle), or in dictating what his 2001 Ford F-150 pickup color would be (it's black, with tan interior, btw.) Price is one thing, color... not negotiable.
Tell her at least it's not
fluorescent yellow like the Lotus Elise I've seen (which actually looks beautiful in that color, but stands out like a sore thumb since only a foreign sportscar manufacturer would dare put that color on any vehicle other than a fire engine.)