The two-color alternation survives every viewing condition: red reads strongly at night, blue stands out at dusk and to color-blind drivers who may miss pure red. The contrast flash is simply the most attention-grabbing pattern we've standardized on.

Can I adjust the flash speed?

The POLICE effect runs an authentic preset rhythm; long-press to tune it. For fully custom emergency patterns — say red-blue-white bursts — the Pro Timeline editor lets you script your own sequence.

Police Lights App: Red & Blue Flashing Screen

Q: Is it legal to use a police lights app?

Using it at a party, in a costume, on a film set or as a toy is fine. What's illegal in most places is impersonating law enforcement or displaying flashing red-blue lights from a moving vehicle on public roads. Broken down on the shoulder, an emergency flasher pattern to be seen is normal use — but know your local rules.

Color Flashlight Team · Updated July 2026 · 3 min read

Short answer: the POLICE effect in Color Flashlight – ScreenFlash alternates full-screen red and blue in the rapid pattern everyone recognizes. People reach for it for three legitimate reasons: being seen during a roadside breakdown, selling a costume or film scene, and — let's be honest — because kids find it endlessly fun.

What the effect does

Tap once and the entire display snaps between saturated red and blue with a strobe-style cadence modeled on real light bars. Because it's the screen — not the tiny LED — the light is visible across a wide angle, which is exactly what you want when the goal is being noticed.

Start the police lights

Get ScreenFlash free and tap the power button.
Swipe up to Effects and tap POLICE.
Long-press the effect to fine-tune speed and looping; the wakelock keeps it flashing hands-free.
Prop the phone where it's most visible — dashboard for a breakdown, shelf for the party, hand for the costume.

Color Flashlight – ScreenFlashUnlimited colors · Strobe · SOS · Free

Free on theApp Store

Where it earns its keep

Roadside visibility: hazard flashers plus a bright flashing screen in the rear window make a stopped car dramatically more visible at night. For a recognized distress pattern, switch to SOS mode.
Costumes & props: cop, robot or cyberpunk costume, school play, indie film — a phone tucked into the outfit sells the scene without wiring anything.
Play: toy patrol car chases around the living room, powered by a phone on the roof. Pair a second phone running white strobe for full TV-drama effect.
Parties: alternate it with Disco mode for high-energy set pieces.

⚖️ Use it responsibly: never use flashing red-blue to pull anyone over, mount it on a moving vehicle, or imply you're law enforcement — that's a crime almost everywhere. Costumes, props, parties and being-seen-while-stranded are what this is for.

Frequently asked questions

Is it legal to use a police lights app?

For costumes, parties, film and play — yes. Impersonating police or running red-blue flashes from a moving vehicle on public roads is illegal in most places.

Why red and blue?

The alternating contrast survives night, dusk and color-blindness — it's the most attention-grabbing standardized pattern.

Can I adjust the speed?

Yes — long-press to tune, or script fully custom patterns in the Pro Timeline editor.

Police Lights App: Red & Blue Flashing Screen

What the effect does

Start the police lights

Where it earns its keep

Frequently asked questions

Is it legal to use a police lights app?

Why red and blue?

Can I adjust the speed?

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