Traffic signal lights — California Permit Test
Traffic signal lights on the California permit test — 12 rules, each with the reason behind it and a question on it while it is fresh.
The rules
A solid red traffic signal light means stop.
It is the plainest instruction on the road, and the one every other driver is counting on.
A red traffic signal light means STOP.
A red arrow means stop, and you may not turn at it; remain stopped until a green light or green arrow appears.
An arrow is aimed at one movement, so a stopped arrow refuses that movement and nothing else.
A red arrow means STOP. Do not turn at a red arrow. Remain stopped until a green traffic signal light or green arrow appears.
A flashing red signal light means stop, and after stopping you may go when it is safe.
It works exactly like a stop sign that happens to be lit up.
A flashing red signal light means STOP. After stopping, you may go when it is safe.
A solid yellow traffic signal light means caution and that the light is about to turn red; stop if you can do so safely.
Yellow is the end of your turn, not a few free seconds tacked onto it.
A yellow traffic signal light means CAUTION. The light is about to turn red.
If you cannot stop safely for a yellow light, cross the intersection cautiously.
Braking hard with a car close behind trades one risk for a worse one.
If you cannot stop safely, cautiously cross the intersection.
A yellow arrow means the protected turning time is ending and the signal will change soon.
The oncoming traffic that was being held back is about to be let go.
A yellow arrow means the protected turning time is ending. The signal will change soon.
A flashing yellow traffic signal light is a warning to proceed with caution: slow down and be alert, but you do not need to stop.
Something up ahead needs your attention, which is why the light is flashing at all.
A flashing yellow traffic signal light is a warning to PROCEED WITH CAUTION.
A flashing yellow arrow lets you turn, but the turn is not protected, so yield to oncoming traffic first.
The oncoming cars have a green of their own, and nothing is holding them back for you.
You can turn, but your turn is not protected from other traffic.
A solid green traffic signal light means go, but you should still stop for any vehicle, bicyclist or pedestrian already in the intersection.
Somebody caught in the middle when the light changed has nowhere to go but forward.
A green traffic signal light means GO. You should still stop for any vehicle, bicyclist, or pedestrian in the intersection.
Proceed on a green light only if you have enough space to do so without creating a danger to any oncoming vehicle, bicyclist, or pedestrian.
A green light is permission to go, not a promise that the space to go into is there.
Only proceed if you have enough space without creating a danger to any oncoming vehicle, bicyclist, or pedestrian.
A green arrow means go in the direction the arrow points, and the turn is protected because oncoming vehicles are stopped by a red light.
It is the one turn where nothing is coming the other way, and it lasts only as long as the arrow does.
A green arrow means GO in the direction the arrow is pointing.
When a traffic light is not working, stop as if the intersection were controlled by stop signs in all directions, then proceed cautiously when it is safe.
Nobody can tell whose turn it is, so everybody takes the turn a four-way stop would give them.
When a traffic light is not working, stop as if the intersection is controlled by STOP signs in all directions.
On the test
What does a solid red traffic signal light mean?
Come to a stop and wait. It is the plainest instruction on the road, and the one every other driver is counting on. California Driver’s Handbook, p.33: “A red traffic signal light means STOP.”
How this works
Most practice tests hand you a bank of questions and leave the manual somewhere else. This one puts them together.
You read one law and the reason behind it, then answer a question on that law while it is still fresh. Get it right and you move on; get it wrong and you have found the gap while it is cheap to fix, not on the morning of the exam.
Learning one rule at a time, and proving it immediately, is what turns a manual you skimmed into something you actually know — and it makes studying feel like getting somewhere rather than like waiting to find out.
What it costs
- One payment, once — not a subscription. Nothing renews and there is nothing to cancel, for an exam you sit one time.
- Free to start: a 10-question test and the first section of cards. No sign-up and no account.
- Paying opens the rest of the cards, unlimited full-length practice tests, and retests built from exactly the questions you got wrong.
- Every level up to Prepared — 3 tests passed in a row.
- Do the work, fail the real exam, and we refund you.
Where these come from
Every rule here is checked against California Driver’s Handbook, published by the California Department of Motor Vehicles, and against the state code itself. Last checked 2026-09-21.
- src/assets/drivers-manuals/CA.pdf (California Driver’s Handbook, DL 600 ENGLISH (REV. 6/2025), retrieved 2026-09-14; sha256 pinned in SOURCES.json)
- src/assets/drivers-manuals/CA.pages.txt (the pdftotext -layout fixture every citation here was cut against and verified against; sha256 pinned in SOURCES.json)
- src/assets/drivers-manuals/SOURCES.json, CA entry — the folio offset of 6 and its basis, the three non-law pages, the two sign gallery pages, and the record of why California’s exam shape is this app’s own
- docs/plans/chosen-exam-shapes.md section 5 — the decision that a state publishing neither exam figure ships 40/32 with both disclosed
- docs/plans/how-to-build-laws.md — the rule that the handbook is the syllabus and nothing enters this file without a page in it