Wearable safety lights. Early morning and evening hours are often the only time busy people can fit in a run or a bike ride. It’s dark, and low visibility can make it a dangerous time to be out and about.
25 ways to run faster - Walk for 3 minutes at 4.0; run at 7.0 for 90 seconds; then sprint at 9.5 for 30 seconds -- repeat until you have completed 30 minutes (should be close to 4 miles!) -- then jog for 3 minutes to cool-down.