LED traffic and road information signs

What is an LED road information sign used for?

An LED road information sign is used to give drivers timely information they cannot get from fixed signage. Typical messages include road closures and diversions, landslide and flood warnings during the monsoon, roadworks, congestion ahead, festival traffic arrangements around Dashain and Tihar, and general safety reminders.

The defining requirement is that the message is current. A sign warning of a closure that has already cleared teaches drivers to ignore it, so the operating arrangements — who updates the sign, from where and how quickly — matter as much as the hardware.

Signs fall into two broad types: text-only variable message signs, typically with amber or full-colour characters, and full-colour graphic screens that can show symbols, maps and text. Full colour is more flexible; text-only is simpler and can be easier to read at speed.

How should text and pitch be chosen for legibility at speed?

Legibility at speed depends on character height and contrast far more than on fine resolution, so road signs use coarse pitches and large characters. A driver may have only a few seconds to read the sign, so messages should be short — a few words per line, a few lines at most.

Pixel pitch for road signs is usually in the P10 to P20 range, because the closest viewer is still many metres away. The general rule — pitch in millimetres roughly equals the closest comfortable viewing distance in metres — gives a starting point, but for road use the real driver is character height, which must be large enough for the approach speed.

Nepali and English text both need testing. Devanagari script has more detail than Latin characters, so characters must be generous in size and the font chosen for clarity, and the message should be checked on the actual screen at the actual distance before go-live.

What brightness and sealing does a road sign need?

A road sign needs outdoor brightness of at least 5,000 nits, automatic dimming at night and IP65 sealing on both front and rear. Full daytime brightness is needed to read the sign against a bright sky or low sun; the same brightness at night dazzles drivers, so a light sensor that dims the sign after dark is a safety feature, not an extra.

Sealing is non-negotiable. Road signs are fully exposed to monsoon rain, spray from vehicles and dust, and a front-only rating leaves rear electronics vulnerable. Specify front-and-rear IP65 and ask for evidence.

Wide viewing angles help on curved approaches, and anti-glare module surfaces improve contrast in direct sun.

How are road signs updated and monitored remotely?

Road signs should be updated and monitored remotely, typically through a cloud content management system over 4G or fibre. Sending an engineer to each sign to change a message defeats the purpose, especially on highways where a closure needs to be shown within minutes.

A proper system lets the operator push a message to one sign or a group, schedule messages, and see the status of each sign — whether it is online, what it is showing and whether any modules have failed. Monitoring matters because a blank or garbled road sign can be worse than no sign.

Access control and an audit trail are also important on a public system: decide who can publish, require approval for unusual messages and keep a record of what was shown and when.

How should power and structures be designed on roads?

Road signs need reliable power with surge and lightning protection, and structures engineered for wind, vehicle impact and seismic loads. Many sites are remote from good supply, so backup power is worth considering for signs that must keep showing safety warnings during cuts.

Gantry and roadside pole structures need proper foundations, crash protection where vehicles could strike them, and safe access for maintenance without closing the road. Front-service cabinets simplify maintenance on single-pole mounts.

On hill roads, the site itself can be at risk from landslides and erosion, so the location and foundation should be chosen with the road authority’s knowledge of the slope.

What should be settled before procuring traffic signs?

Before procurement, settle who owns the signs, who operates them, what messages they will show and how they will be maintained. These decisions shape the technical specification and avoid buying hardware that nobody is set up to run.

Road signs on public roads involve the relevant road and traffic authorities, and requirements for placement, message content and structures vary and change over time. Confirm them with the responsible authorities before tendering.

The specification should then cover pitch and character height, brightness and dimming, IP rating front and rear, remote management, power protection, structure and a warranty with local support. Our LED displays carry a two-year manufacturer warranty honoured locally, with spares held in Kathmandu, and we survey sites before giving a firm specification.

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