Vehicle equipment, inspection and registration

Key points

1. Vehicles need a safety inspection at least once a year; ambulances every 6 months, and new vehicles not until 2 years after first sale.

   Source: Handbook p. 18

   “at least once a year, except that ambulances must be inspected once every six months, and new vehicles do not need to be inspected until two years after their initial inspection”
   Hawaii Driver's Manual, Handbook p. 18

2. A red light showing from the front, or a blue light visible outside the vehicle, is illegal except on emergency vehicles.

   Source: Handbook p. 18

   “A red light showing from the front, or a blue light visible outside of the vehicle, except on authorized emergency vehicles;”
   Hawaii Driver's Manual, Handbook p. 18

3. A bell, exhaust whistle or siren is also prohibited except on emergency vehicles.

   Source: Handbook p. 18

   “A bell, exhaust whistle or siren, except on authorized emergency vehicles;”
   Hawaii Driver's Manual, Handbook p. 18

4. Children under 4 must be in a child restraint, and children under 8 need a booster seat if under four feet and less than forty pounds.

   Source: Handbook p. 20

   “Children under age 4 must be in a child restraint; children under age 8 must be belted on a booster seat if the child is under four feet and less than forty pounds.”
   Hawaii Driver's Manual, Handbook p. 20

5. Replace tires with less than 1/16 inch of tread.

   Source: Handbook p. 20

   “Replace tires that have less than 1/16 inch of tire tread.”
   Hawaii Driver's Manual, Handbook p. 20

6. Power steering should have no more than 2 inches of free play, or 3 inches without power steering.

   Source: Handbook p. 20

   “There should be no more than two inches of free play in the steering wheel, if you have power steering (check with the motor running); or 3 inches, if you do not have power steering.”
   Hawaii Driver's Manual, Handbook p. 20

7. If your address changes, notify the county agency in writing within 30 days.

   Source: Handbook p. 21

   “must, within thirty (30) days after the change, notify the appropriate county agency,”
   Hawaii Driver's Manual, Handbook p. 21

8. Motorcycles, trailers and semi-trailers show a rear plate; all other vehicles need plates on both the front and rear.

   Source: Handbook p. 23

   “Motorcycles, trailers and semi-trailers must display a license plate on the rear; all other vehicles must display a license plate on both the front and rear.”
   Hawaii Driver's Manual, Handbook p. 23

Numbers to know

3 questions from the Hawaii practice test

1. 1. When does Hawaii's manual say to replace tires?

   1. When tread is under 1/2 inch
   2. Every two years regardless
   3. When tread is less than 1/16 inch
   4. Only after a blowout
   Show answer

   When tread is less than 1/16 inch. Replace tires that have less than 1/16 inch of tread, and check that the vehicle does not pull to either side under braking; a simple brake test is to apply the brakes rather hard at 4 to 8 mph in a safe place. Proper inflation extends tire life and improves handling, and good tread is the main defense against hydroplaning, which can begin at 35 mph.

2. 2. Which Hawaii vehicle occupants must wear seat belts, and what restraint rules apply to children?

   1. Only front seat occupants
   2. Only the driver
   3. All front and back seat occupants; children under 10 need a child restraint or booster unless at least 7 and over 4 feet 9 inches
   4. Only children
   Show answer

   All front and back seat occupants; children under 10 need a child restraint or booster unless at least 7 and over 4 feet 9 inches. Section 291-11.6 of the Hawaii Revised Statutes requires every front and back seat occupant to wear a seat belt, so limiting the rule to the driver, the front seat, or children is wrong. Children have added rules under section 291-11.5: under two in a rear-facing harnessed seat, two to under four in a harnessed seat, and four to under ten in a harnessed seat or booster. A child aged seven to under ten who is over four feet nine inches may use a correctly fitted lap and shoulder belt instead.

3. 3. Which equipment is prohibited on a Hawaii vehicle that is not an authorized emergency vehicle?

   1. A bell, exhaust whistle or siren, a front red or blue light, and a muffler cutout or bypass
   2. Fog lights
   3. A backup camera
   4. A roof rack
   Show answer

   A bell, exhaust whistle or siren, a front red or blue light, and a muffler cutout or bypass. Vehicles other than authorized emergency vehicles may not have a red light showing to the front or a blue light visible outside the vehicle, a bell, exhaust whistle or siren, or a muffler cutout, bypass, or muffler louder than original equipment. These rules keep emergency signals meaningful and control noise. Equipment violations are cited on inspection and during traffic stops, so remove any aftermarket device that breaks the rule.

Source: the Hawaii Driver's Manual, Chapter II: Vehicle Equipment and Inspection. This lesson is a plain English summary, not the law itself; where it differs, the manual and the statute govern. Last checked 2026-09-27.