Well, empirical studies based on five locations around the Greater Boston Area have determined that...
(drum roll please)
...sodium streetlights (the brownish kind) apparently emit radiofrequency noise that is exactly the right freq to completely jam my !!$?#!?**#@?!@ car door remote. Not all of it; just the unlock frequency. Sigh. So owners of 1996 Toyota types, beware of those gloomy brown parking lots. Yes, before anyone asks, I remembered to just use the key. :-) However, it's a real pain to replace the batteries in those things, and that's what I did thrice...