Dear Car Talk:

Why do convertibles and coupes have such large doors, which makes it hard to get in and out in tight parking spots? Why can’t they have four normal-sized doors? -- Raymond



I guess the autobody repair lobby is very powerful, Raymond. Those supermarket parking lot dents have sent a lot of their kids to college. And on to medical school.

Actually, the reason convertibles (and traditional coupes) have only two doors is because they have no “B-pillars” to which rear doors can be attached.

Cars generally have between one and four structural pillars that go from the bottom of the car to the roof. Those structural pillars provide rigidity and safety, so the car doesn’t fold like a used Amazon box after you open the top and bottom flaps.

The A-pillar is the forward-most pillar, the top of which holds the windshield.

The B-pillar is the pillar between the front and rear doors.

The C-pillar is the next most rearward pillar. On sedans, it holds the rear window. And on station wagons or SUVs, there’s a D-pillar, which is at the very back of the vehicle.

Convertibles only have A-pillars. Coupes have nothing but A-pillars and C-pillars. In order to hang a door, you have to attach the hinges to something. Obviously, the front doors attach to the A-pillars.

In a sedan or SUV, the rear doors attach to the B-pillars. But in a coupe or convertible, there’s no B-pillar, so there’s nothing to attach the rear doors to.

And because they can’t use four doors, they make the two doors they have bigger to provide at least some access to the back seats.

So, should you be unlucky enough to have to sit in the back seat of a coupe or convertible, you can at least squeeze your way in through that larger door opening, rather than diving in through the rear window.