Nearly half of Chicago’s highest cash-generating speed cameras were on the South Side. Two, including the top $3.1-million camera, are hitting Ward 20 Ald. Jeanette Taylor’s low-income constituents with fines she said they can’t afford.

Cash-strapped Chicago is about to get an injection of money from motorists. The city is installing its controversial speed cameras at four neighborhood parks on Monday, and has plans for eight additional locations in the next few months. The city announced the results from a test of the new technology that showed surprising results. During a December trial,...