How the collision simulation works
Numbered objects, 1 to 9, fly onto a plain map in straight lines. To remove one, you type its number on the number pad. Your job is to stop every collision while removing as few objects as possible: when two will collide, remove one of them, not both. If nothing will collide, or every conflict is dealt with, press 0. Candidates warn that once you press 0 you cannot remove anything else in that scenario.
Scenarios start with two slow objects and build to seven or more at once, and some collide a second or two after they appear. Some scenarios have no conflict at all. Objects that collide turn red, which candidates describe as the only feedback in the whole ATSA.
In part 2, arithmetic appears at the bottom of the screen while the traffic keeps moving: a sum with four options, which candidates say run from lowest at A to highest at D. Since the move to Pearson VUE the answers go on the A, S, D and F keys. Each sum is reported to show for 2 to 3 seconds, and you can still answer until the next one appears, so a keypress just as a new sum arrives counts for the new one.
How to approach the collision simulation
Work each scenario in this order:
- In the first second, scan for pairs on converging lines that will reach the crossing point together.
- Deal with the soonest conflict first. A collision two seconds away beats one ten seconds away.
- Look for an object in two conflicts. Removing it clears both with one keypress.
- Remove one object from each conflicting pair, never both.
- Before pressing 0, check every remaining path once more. After 0 there is no way back.
- In part 2, keep the traffic clear first and do the sums second. Estimate big products from their size rather than working them out.
Worked example
Five objects enter. Object 3 is on course to hit object 7 in about two seconds and object 5 a few seconds later. Objects 1 and 4 are crossing paths, and object 2 meets nothing. Remove 3 first: one keypress clears both of its conflicts, where removing 7 and 5 would take two. Then remove 1 or 4, either one. That is two removals, the fewest possible. Leave 2 alone, and press 0 once you are sure nothing else will meet.
In part 2, the sum 36 × 14 appears with options A 404, B 504, C 604 and D 704. Round it: 35 × 14 is 490, so the answer is just over 490. That is B, 504, on the S key.
Tips for the real collision simulation
- Do the practice scenarios. Candidates report practice rounds before most sections, and this is the one where the keys matter most.
- Accept a few collisions. Candidates describe objects meeting a second or two into a scenario, before anyone could react.
- Do not remove objects that are not in conflict. Removing more than needed is reported to count against you.
- Learn the number pad by feel, so your eyes stay on the map while you remove objects.
- Hold your keypress when a new sum appears, or your answer lands on the wrong question.
- Answer the sums when the traffic allows. Correct sums are reported to earn credit with nothing lost for a wrong answer, so a quick estimate beats leaving one.
Practise the collision simulation on CogniPrep
Our simulation runs two parts of 15 scenarios, from 2 objects up to 9, with about one scenario in five free of conflicts so the 0 key gets used. Part 2 adds two or three sums per scenario, each shown for about two and a half seconds and answered with A, S, D and F, and a new sum sometimes follows straight on so you can practise the wrong-question trap. Your score out of 100 uses our own weights, because the FAA publishes none: 50% for conflicts prevented, 25% for removing only as many as needed, 10% for the 0 key and 15% for arithmetic. On a phone you remove objects with an on-screen keypad rather than by tapping them.