Texas Permit Test 6 Question You must dim your high beam lights when within: Answers 100 feet of an oncoming vehicle. 250 feet of an oncoming vehicle. 300 feet of an oncoming vehicle. 500 feet of an oncoming vehicle. Explanation You must dim your high beams whenever you are within 500 feet of an oncoming vehicle. Answer Statistics 27.63 % of our users get this question wrong. This questions is relatively Easy. Texas Permit Test This questions appears in the following tests: Washington Practice Test