It's bleeding obvious that walking uses more energy per mile. Imagine walking a completely flat mile at 4mph, then cycling the same at 4mph.
MET is a time based metric (metabolic rate) but the graph presta posted is distance based.
Typical MET # ranges
People walking 'normally' v cycling 'normally', on the flat, will use less energy, per time unit.
- Walking: ~2.8–3.5 MET (easy, 3.0 mph) up to ~5.0–6.0 MET (brisk, 4.0–4.5 mph; incline raises it further).
- Running: ~7.5 MET (jogging) to 9.8+ MET (6.0 mph/9:40 per mile) and higher with speed or hills.
- Cycling: ~4–6 MET (casual 10–12 mph) to 8–10 MET (12–16+ mph).
- Scooter Riding (not 'e-'): ~6-8 MET (casual 7–9 mph) to 9–11 MET (10–14 mph).
# MET (metabolic equivalent): which translate activity intensity into a multiplier of your resting metabolism. One MET is your resting burn; higher METs mean more oxygen use and more calories.
The paper linked in OP has e-scooter at 2.14 METs, walking at 3.12 METs and driving at 1.42 METs.
MET is a time based metric (metabolic rate) but the graph presta posted is distance based.