Trolling for truckers....
I was going to guess trolling for lot lizards (hookers) but doing it in a PI with antenna or not is going to be pretty obvious. A pickup truck with an 8 foot whip antenna would be more incognito at a truck stop than an intereceptor. Those truckers see those cars all day long on the road marked or unmarked and can probably identify the head/tail light pattern at distance.
Now if undercover isn't the goal but you just want to avoid unsightlyness, there are NMO mount antennas that will work better but not be as gaudy as the typical Firestick or Wilson. Easily installed by your usual radio shop. Same design as the usual low band antennas used on police/fire vehicles.
A popular choice for State Patrol, Land Management and serious CB applications, these MLB lowband antennas provide superior performance for a variety of lowband applications.
www.pctel.com
shopwiscomm.com
Ok so I read deeper and saw it was supposed to be for convoy use. I'd still recommend the Maxrad, it would work and look fine on the trunk lid on either side or replacing the low profile in the center. I have agencies near me using the 40MHz versions on their new PIs.
Those superload convoys can stretch out quite a bit and I still think you will have range issues with the President antenna. But by all means let us know if it's been working better than expected.