Simply put, because while it would slightly reduce road/rail risk it would increase other risks by far more:
1 - Increased risk from cars speeding (to beat new barriers which will be down for up to 5 minutes vs current 50 seconds)
2 - Massive increased risk to Meldreth residents, as all emergency service either wait extra 3-4 minutes at barrier OR divert down A10 and back up Meldreth High Street, at least 7 minutes. Network Rail don't even CONSIDER that apparently until AFTER permission granted!!!
3 - Inconvenience and traffic queues from much longer down times - current 50 seconds will increase to Shepreth's or WORSE. Someone crossing 4 times a day can look forward to at least ten minutes a day wasted...
Don't take my word for it:
You can find the Inspector's Report here:
Network Rail (Cambridge re-signalling) order inspector's report
And the letter from the Department of Transport here:
Network Rail (Cambridge re-signalling) order decision It is true that a double barrier makes it impossible for either a car/pedestrian/cyclist to cross when the barrier is down.
ALSO
1. The local Rail User Group has no evidence of any incidents or near misses at the crossing throughout the 14 years of its existence.
2. There have been no accidents at the crossing that a double barrier would have helped prevent. In fact to see Network Rail's data required a Freedom of Information request and only came on 1st September, despite the September 23rd objections deadline. In the past 25 years according to that Network Rail data there has been one recorded incident where a double barrier could potentially have improved safety (and even this was NOT classified as a 'near miss). Almost half of the 'incidents' weren't even related to the crossing but to others in the area and misrecorded!
3. It will reduce train usage. Anyone crossing to catch Cambridge bound trains from Shepreth have to allow for ~5 minutes of downtime potentially at both Meldreth Road crossing and then at Shepreth station (which has no footbridge). For some at least it won't feel worth the hassle and they'll now drive instead.
4. The new longer downtime crossing has its own risks. Double barriers stop cars crossing with a barrier down, but also stop a car being able to get off the track if trapped by barriers. During the week of August 15th 2022 at Shepreth after a very long down time frustrated drivers were crossing nose to tail, and the barriers came down again with a car between them. Luckily there was room for it to get off the track just about before a fast train came through.
5. Only issues for those very near the crossing, but the new crossing will likely require floodlighting like the Shepreth station one. And since the downtime would increase NOT from 2 minutes to 3 and a half, but from 50 seconds to almost four minutes, their traffic modelling is wrong and those living close to the crossing will have constant traffic queues outside their homes.
The bottom line is that Network Rail are going to create a problem on the road where none exists, in order to 'fix' what they have themselves decided is a risk on the railway, despite no evidence of any problem.
To see just how bad the impact will be see what happened when exactly the same change was made at Shepreth Station as reported in the Royston Crow - barriers which are down for exactly the same trains. As the Network Rail representative then said, '3 to 5 minutes is the expected time for the barriers to be down'. That compares to 50 seconds now and the downtimes of 7 minutes+ that frequently happen at Shepreth.
Shepreth level crossing: Frustrations put to Network Rail at Meldreth RUG meeting | Royston Crow (royston-crow.co.uk)
SO WHY ARE NETWORK RAIL PRESSING AHEAD?
A legitimate issue is that sooner or later the current barriers WILL need replacing. And clearly when works need doing we do have to accept temporary road closures - fair enough. But NR had originally suggested an upgrade which would MAINTAIN current downtimes - which would be 'the best of both worlds'. Now they say that is not possible, because...
THEY have decided not to work on upgraded half barriers and only replace them
THEY have decided there is risk at Meldreth Road (based on evidence admitted to be incorrect at the Inquiry)
THEY have decided only double barriers like at Shepreth Station can replace them.
And when planning has been rejected, THEY have decided to do it ANYWAY - because THEY are ONLY responsible for and measured on rail safety, not on any transferred risks some of which are only considered and planned for AFTER permission and construction.