All my old sets have cars with windscreen 4 studs wide. No matter if it is a jeep, truck or what - cars was 4 studs, usually 3823 or 2437. Now, in most modern sets, car windshield is usually 6 studs wide, like 92583.
I'm interested when this transition happened. If it's possible, I'll be also glad to hear why - was this change caused by introduction of other bricks? New "series" of a City theme? General overhaul?