How to approach road-closure route questions

Treat the closed road as unavailable

Do not partially use the named closed road or draw through it because it looks convenient. Start by identifying exactly where the closure affects the normal route.

Find the smallest sensible detour

Look for nearby roads that let you bypass the unavailable section while keeping the overall journey direct. A huge diversion can be technically possible but still be poor route planning.

Rejoin the natural route

After bypassing the closure, look for the earliest sensible point to return to the route towards FINISH. This prevents a local obstruction from turning into an unnecessarily long journey.

Practise with Cassland Road

PCO Topography uses London Lane → Gascoyne Road with Cassland Road closed as the single free practice route. It is a useful first exercise because the closure forces an actual route decision.

Common mistakes when working on closure detours

A common mistake is trying to solve closure detours too quickly. Candidates can recognise the general area yet miss the first important restriction or connection. Slow the decision down long enough to explain why the first road choice works. That small pause is usually cheaper than repairing several later turns after the route has already moved away from the best corridor.

Another mistake is treating every visible difference from the accepted line as the same problem. With closure detours, the useful question is whether the road sequence is wrong or the drawing is merely imprecise. PCO Topography separates those signals so you can prioritise leaving and rejoining the natural corridor at sensible junctions. A route-choice correction should come before cosmetic line placement.

Finally, avoid memorising the shape of one map. Repeat the underlying decision on a different exercise. If you can explain the rule and apply it elsewhere, the skill is becoming transferable. That is why the route bank combines focused practice with full routes rather than asking you to repeat one screenshot until it looks familiar.

A practical study drill for closure detours

Use a three-pass drill. On pass one, inspect the map without plotting and say the likely corridor aloud or write it down. On pass two, plot and submit normally. On pass three, review the first meaningful divergence from the accepted model and state the reason for it in one sentence. This keeps the session focused on decisions instead of random repetition.

For the next attempt, change only the behaviour that caused the main error. If the issue was direction, check arrows earlier. If it was a structure, verify the actual connection. If it was road position, keep the same route choice and place the line more carefully. This controlled correction makes score changes easier to interpret.

Finish by transferring the skill into closure-specific drills. Do not require a perfect score before progressing; require that you can identify what you did, why it was correct or incorrect, and what you would check on an unfamiliar map. That is a stronger preparation habit than simply accumulating completed route numbers.

• Scan before clicking
• Choose the corridor
• Check direction and restrictions
• Plot meaningful junction points
• Submit without revealing the answer
• Review the first major divergence
• Repeat the same skill on a different route