Jimp

[daedalus21]

What is a Jimp? I saw an old Ministry of Transport magazine advert from the Nineteen Forties featuring a Traffic Jimp, so I'm assuming it's a kind of imp, something mischievous to throw you off the right course. I can't find any detail.

[Tichfield]

I found this:

http://journals.cambridge.org/production/actio n/cjoGetFulltext?fulltextid=443318