The same cylindrical screw-top shape for ALL liquids and drinks, in half-, one-, two-, and four-pint sizes. All bottle labels should be one piece of wraparound paper with a single sticky. No more plastic bottles going to landfill or needlessly smashed up by the bin men. Bring back weekly bottle collections and have Unilever pay to make more or buy them back cheap. Proper recycling, not just shipping trash to the Nords so we can claim we're closer to carbon neutral.
There's a similar idea brewing for cardboard packets and boxes, but nowhere near fully formed yet.
Traffic lights that turn into zebra crossings off peak.
Turning left on red when clear.