REQUEST FOR STAGGERED BARRIERS at Headington Roundabout subway

On 13/02/24, 11:30 am I witnessed a cycle accident in the Headington Roundabout subway connecting Green Rd to the Roundway. A 10 yo child and his mother, both on bikes, were rounding the corner of the subway that I have indicated (toward Green Rd) when a food delivery e-bike rounded the same corner at speed in the opposite direction (toward Roundway). The e-bike collided with the child, who was ejected from his bike and collided with the side of the tunnel. Mercifully, the child suffered surface wounds, but from the trajectory that he followed as he was ejected from his bike he could have suffered life-altering injuries. None of the parties involved in the accident were dismounted from their bikes/e-bike. While we waited for an ambulance in the tunnel, upwards of 45 min, several cyclists also passed us by, none of whom had dismounted either. This is a major problem: the tunnel has ramps at either end, so that people entering the tunnel on bikes pick up speed as they go down. The tunnel also has a turn, preventing visibility along its whole length. Although the entrances at both ends of the tunnel warn cyclists to dismount, from my experience that day this is not followed by the vast majority of cyclists. I would like to request urgently that staggered barriers be placed at either end of the tunnel, so that cyclists are forced to dismount, or at the very least significantly slow down as they manoeuvre around the barriers. The accident I witnessed could have been avoided if that e-bike (more similar in size and weight to a motorcycle than to a bicycle) had been forced to slow down. Staggered barriers will do that even if cyclists/e-bike riders still don't dismount.