This takes advantage of custard's, better known, explosive properties...

link

This site has entertained me all day so I thought I'd share. Somehow it seems perfectly suited for Simpson. People using ample knowledge bases that aren't fully tapped at work to devise ridiculous and curiously attainable schemes. 'Attainable,' if you really could convince the municipality to fill speed bumps with custard. Phrases like this,"I think the term you're looking for is 'dilatant', not 'thixotropic'. Thixotropic means that it'll solidify if left still, while dilatant means the required shear force deviates positively from Newtonian behaviour, i.e. shear thickening. Just for the record, 'pseudoplastic' is the opposite of dilatant -- it means shear-thinning.", are used in regards to pudding filled road hardware. Genius!