Start with the operational details, not just the dates
An RFP that only lists trip dates and passenger counts forces every vendor to guess at the rest, which means their quotes will all be built on different assumptions. Include exact pickup and drop-off addresses, whether the trip is one-way or round trip, how many hours the vehicle needs to be on standby versus actively driving, and whether the schedule includes any multi-stop routing. If you're recurring, say so upfront and specify the frequency, because recurring contracts price differently than one-off charters.
Ask for proof, not just promises
Any vendor response should include their DOT number, current insurance certificate limits, and a summary of their safety rating history through FMCSA's SAFER system. If a vendor won't provide this before contract award, that's worth noting as a red flag rather than assuming it'll come later. We include this documentation in every proposal without being asked, because government and corporate buyers increasingly require it as a baseline, not an extra.
Fleet age and backup vehicle policy
Ask each vendor directly what their average fleet age is and what happens if the assigned vehicle breaks down. A vendor with a backup vehicle policy in writing is a different risk profile than one who tells you 'we'll figure it out.' For time-sensitive events like conferences or shuttle contracts tied to a specific schedule, this answer matters more than the quoted rate.