But as training? What benefit do you get by going fast tucked in behind a bus? Why not just get a mate in a car to tow you along
I do the Derny paced sessions on the velodrome. It’s a way of getting in some high intensity work but at a practiced pace. Out on the open road, it’s great to be able to sit there practicing sprint efforts or high speed race run ins without actually being in a race or having 100 other idiots around you all sprinting for the line. Means you cut out the one massive variable of wind and just concentrate on technique, heart rate, power under replicable conditions.
In real life situations…
I used to work at Heysham and would ride home down the connecting road between Heysham and Lancaster, a 3-mile long almost flat, dead straight road with no junctions or lights. If you could get behind one of the fully laden lorries coming out of the port as it slowly crested the incline, you’d get a tow right down this road. 50mph limit which the trucks mostly stuck to so it was great sitting in right behind them. Fastest I had down there was 56mph and that was spinning out a 53×12.
The only dodgy moments were when the trucks out accelerated you (that’s why you need a fully laden truck, they accelerate much more slowly!) and you got the full blast of a sudden 40+ mph headwind. That caused a few scary moments. Wouldn’t do it in traffic though.