Reigate Hill Interchange

Reigate Hill Interchange is junction 8 of the M25. It is standard roundabout interchange with the A217 dual carriageway crossing the M25. There is an additional exit on the southern side which provides local access to Reigate Hill Castle & a residential property. The one special thing about this interchange is that the diverge for CW traffic is an extra mile down the road at the bottom of the hill, this is such to prevent dangerous weaving by cars/vans between slower moving lorries continuing along the M25.

History

1976

The M25 J6-J8 was opened, as such the M25 only existed to the East of the junction, however the entire junction was built, but just with no traffic passing under. It is unknown whether the slip-roads onto and offof the M25 were D2M or D3.

1985

The M25 J8-J10 was opened, now the M25 fully passes under the interchange as a D3M

1990s

Various parts of the M25 was widened to a D4M standard in the 1990s, this included either side and through J8, with the hard shoulder passing the otherside of the piers, at this time the CW slip road was moved around a mile backwards to the bottom of the hill. This section of the M25 is one of the steepest gradients on the M25 and UK Motorway network signed as 10% (although TSM suggests rounding to nearest 5%, so could be as low as 7.5%), as such lorries may struggle to maintain a fast speed up the hill in Lane 1, this could block traffic trying to take the exit, so the exit was moved to the bottom of the hill for this reason.

2020s

As part of Highways England's M25 Junction Schemes, Junction 8 would receive some alterations. These were due to start in Spring 2019 and take just short of a year to complete, however have been proposed to after Jan 2020 to minimise conflicting closures with the M23 SMP which is due to be completed March/April 2020. The changes that would be made are:

• Upgrading Traffic Lights throughout the junction
• Adding extra lanes on approach to the junction (A217 northbound)
• Widening and extending the ACW exit slip road by utilising existing verge.
• Widening of lanes on the roundabout (it appears that it was designed for two lanes, however marked as three lanes)
• Improving road signs and markings
• Widening and realigning the A217 southbound south of the junction to two lanes. (This isn't overly clear, at the moment it is two lanes, and drops one lane onto Gatton Bottom, the change may be that the lane doesn't drop onto Gatton Bottom and instead merges into 2 lane, then a divege can happen for Gatton Bottom.)

Routes

Route	To	Notes
M25	(M3, M4, M40), Heathrow Airport, Leatherhead
M25	(M23, M20), Gatwick Airport, Dartford, Brighton, Croydon, East Grinstead
A217	London (S & SW), Sutton, Kingston (A240)
A217	Reigate, Redhill (A25)