Something new that I noticed last year in my crossings, US and Canada are sharing information a lot more now than they have in the past. I'm flagged in the Canadian Customs database for a minor work-related incident and they always ask me about it when I cross into Canada. On one crossing back into the US I was asked if I'd ever had any issues with Canadian Customs. I'm betting both sides of the border now have complete access to driving records and driving citations.
BTW, my work related incident was not having proper paperwork. I had been advised by my Canadian contact to tell Canadian Customs a different story than what I'd documented in my US paperwork. Glad I didn't take that advice because it would have left me in real trouble back in the US given the type of work I was doing and the paperwork I'd filled out.
Moral of the story, be honest on both sides and make damn sure the story is the same on both sides of the border. Don't volunteer information, don't anticipate the questions, just answer truthfully any questions that are asked. Some questions seem simple but take on different meanings depending on which way you're crossing. For instance, the question "what is the purpose of your visit?" means "why do you want to cross into the country you're not a citizen of?", OR it means "why were you in a country you're not a citizen of?". When in doubt, ask.