It used to be said that the architects of high rise flats ought to be made to live in them. In similar vein, the designers of cycle farcilities like that one ought to be made to cycle in them.
And therein lies the problem. If you don't do any serious cycling, or consult people who do, you will end up with all sorts of issues. OK, the ones like Ritchie's OP are plain daft, as are ones where there are bollards in the middle of the cycle lane and such, as anyone can see that they're not usable. However, cycle lanes don't have to be physically impassable to be borderline useless, but often the problem isn't apparent in the abstract to someone not used to utility cycling.
• Tight turns. There are numerous cycle lanes in Loughborough that require you to perform a 90º turn in the width of a standard pavement immediately after crossing a side road. This isn't impossible, but to do it safely you have to slow to walking pace or less. Given that you're just coming out of a road crossing, this is impractical: it requires you to slow when half-way across the road, thus getting in the way of road users.
• Giving way to traffic approaching from right behind you. Any shared-use pavement or segregated parallel cycle track presents this problem at every side road, and it's especially problematic if you're travelling in the same direction as the lane of traffic nearest to you, which you usually are.
• Being expected to fit in an area of tarmac that's narrower than your vehicle. Just because bicycle tyres are only a few inches wide doesn't mean the bike and its rider is.
• Having to stop and start the whole time. It may be superficially safer to direct bikes on a zig-zag route through a housing estate rather than down the main road, but no serious cyclist is going to voluntarily choose a route that involves give ways every hundred metres. In any case, I'd question the safety aspect here. In estates you tend to get narrow roads with junctions with poor sightlines, and if you're using the estate as a through route (a purpose for which it was explicitly not designed), you'll pass through lots of them. You're far more likely to be the victim of a SMIDSY there than you are on a main road with good sightlines, plenty of space for overtaking traffic and where most other road users are travelling in the same direction.
The problem is that many of these issues are not immediately obvious to someone whose only experience of cycling is going for a walking-speed pootle with their kids in the park.