As the global Intelligent Transportation Systems (ITS) market continues to expand, the Variable Message Sign Trailer (VMS Trailer) has become a core component of intelligent transportation systems. However, the wrong type can lead to message failure, compliance risk, or wasted resources. The following section provides a systematic decision-making framework from the dimensions of technical principles and type comparison to help you accurately match your needs and improve traffic management efficiency.
VMS trailer
VMS is a real-time information display device based on LED/LCD technology, which can dynamically release text, symbols or images by integrating sensors such as traffic flow and weather data. It has evolved through two generations: the early generation required on-site manual programming, while the modern system supports 4G/5G wireless remote control, with response speeds up to the minute level, and is widely used in scenarios such as Amber Alerts and road construction alerts.
Traffic management: real-time road warning (congestion, accidents), lane control guidance
Public safety: extreme weather alerts (heavy rain, snow and ice), emergency evacuation notification
Commercial scenarios: temporary event advertising, parking lot space guidance.
There are two main types of Variable Message Signs (VMS) Trailers:
| Type | Portable / Mobile VMS Trailer | Fixed / Permanent VMS Trailer |
| Deployment Method | Quick to assemble/disassemble, ideal for temporary use (e.g., exhibitions, emergency response) | Requires professional installation, suitable for long-term fixed locations (e.g., highway hubs) |
| Display Size | Usually ≤5㎡, balancing mobility and visibility | ≥8㎡, supports large-area dynamic information display |
| Typical Scenarios | Urban temporary control zones, large event security | Highway main roads, tunnel entrances, urban arterials |
| Cost Structure | Low initial investment, low relocation cost | High installation cost, stable long-term maintenance cost |
| Target Users | Municipal emergency departments, small to mid-sized ad agencies | Traffic management authorities, large highway operators |
Before choosing a VMS Trailer Display, you need to pinpoint your requirements by asking the following questions:
| Evaluation Dimension | Specific Question | Example Answer |
| Primary Purpose | Is it for traffic control, event promotion, or emergency alerts? | Real-time traffic updates during highway construction |
| Mobility Frequency | How often is it moved per week?
Is cross-region transport required? |
Moved daily, needs to support multi-city deployment |
| Information Type | Text only, or does it include graphics and logos? | Needs to display arrow symbols and corporate logo |
| Deployment Environment | Urban roads, highways, or remote areas? | Coastal, windy areas—requires typhoon-resistant design |
| Viewing Distance | How far away is the intended audience when viewing the sign? | Highway setting—must be clearly readable from 200 meters away |
Size Selection:
Long-range scenarios (e.g., highway): A display size of 3 meters or more is recommended to ensure clear readability at high speeds.
Urban or low-speed scenarios: 1.5-2.5 meter displays are more cost-effective, balancing readability with ease of transportation.
Display technology:
High-definition LED panels: suitable for scenarios where graphics and animations need to be displayed (e.g. commercial advertisements), with a recommended resolution of ≥100 pixels per square meter.
Monochrome LED panels: Suitable for text-only messages (e.g. speed limit reminders), with lower costs and less energy consumption.
Brightness standard: 3000-5000 nits (cd/m²), ensuring no reflection in bright light and no glare in low light.
Solar VMS trailer
The competitiveness of a modern VMS trailer is centered on intelligent features:
Real-time update: Through 4G/5G network or Wi-Fi connection, it supports remote modification of content by cell phone APP and computer without the need of personnel presence. For example, the detour route can be updated within 30 seconds in case of sudden congestion.
Automated scheduling: preset messages for different times of the day (e.g. “Congestion Ahead” is displayed in the morning rush hour, and “Drive with Caution” is displayed at night), reducing the cost of manual operation.
When verifying the quality and reliability of the VMS Trailer, the material and power supply system are the basic guarantee. The materials must be UV, water and dust resistant to IP65 or above, which is usually achieved by using an aluminum alloy frame with an anti-corrosion coating, a combination that can withstand outdoor high temperatures, heavy rains and salt spray, while reducing the weight of the equipment for easy transportation. Power supply system, in order to meet the no external power supply ≥ 12 hours of endurance requirements, the mainstream program is a combination of solar panels and lithium batteries, the average daily 5 hours of light can be efficient photovoltaic conversion into electricity storage, with intelligent power management system automatically optimize the logic of charging and discharging, to ensure that the equipment continues to operate stably at night or in remote areas.
Stability and ease of maintenance directly affect the actual use of the VMS trailer experience. Stability should be realized through the design of wind resistance level ≥8, and adjustable legs and weighted chassis are the core configurations – the former can flexibly adjust the height according to the levelness of the ground, and the latter reduces the center of gravity through thickened steel or weighted blocks, and the combination of the two can effectively resist strong winds of 17.2-20.7m/s; some high-end models also introduce gyroscope sensors to ensure real-time balanced operation and maintenance.
Convenient maintenance relies on modular design, display units, power supply components, etc. are connected by standardized interfaces, and a single faulty module can be quickly disassembled and replaced within 10 minutes. With remote diagnostic function to warn potential problems in advance, it significantly reduces the on-site maintenance time and cost, and ensures the equipment’s efficient operation.
Solar VMS trailer
Different regions have clear regulations on the installation, display content and light pollution of VMS trailers:
U.S.: Compliance with the Federal Highway Administration’s (FHWA) Manual on Uniform Traffic Control Devices (MUTCD) is required, such as character height and flashing frequency restrictions.
EU: CE marking is required, and display brightness must not exceed 5000 nits to avoid glare to drivers.
China: Compliance with GB 5768 series of national standards, e.g. character height of highway warning signs should be ≥ 40 cm.
An authoritative study by the U.S. National Highway Traffic Safety Administration (NHTSA) shows that the traffic accident rate on roadways equipped with LED VMS trailers is 23% lower than that of traditional static signs, which reveals the key role of dynamic information systems in preventing accidents. This data reveals the key role of dynamic information system in preventing accidents.
Its core mechanism is reflected in two aspects: First, early warning ability — when a sudden road accident, VMS trailer can release warning information within 1 minute, and rear vehicles can take braking measures in advance due to real-time reminders, and the average braking distance can be shortened by 15 meters, which significantly reduces the risk of rear-end collision; second, intelligent flow guidance — By analyzing real-time traffic data, the VMS trailer dynamically displays diversion routes and guides vehicles to change lanes in an orderly manner, which reduces the average clearing time of congested road sections by more than 30%, easing the pressure on main roads and reducing the probability of cut-through accidents caused by congestion.
Solar VMS trailer
In the field of traffic information transmission, VMS trailers show significant generational differences compared with traditional static signs. In terms of information timeliness, traditional signs need to rely on manual on-site replacement of content, from the discovery of changes in road conditions to the completion of the information update often lag for several hours or even longer, while the VMS trailer realizes minute-level remote real-time updating through the network, for example, heavy rain can be instantly switched to “rainy day, slippery road, speed limit 60km/h”. In terms of environmental adaptability, the fixed brightness design of traditional signs leads to blurring of content reflection under strong light and difficult to recognize under low light, while the VMS trailer is equipped with automatic light-sensing adjustment technology, which can maintain constant brightness (3000-5000 nits) in extreme temperature difference environments ranging from – 30℃ to 70℃, ensuring no glare during the day and no glare at night.
In terms of message carrying capacity, traditional signs are limited to fixed text or simple patterns, while VMS trailers support mixed-text, animation and multi-language switching. For example, at international transportation hubs, bilingual warnings can be displayed synchronously or construction detour routes can be dynamically guided by animated arrows, which greatly improves the accuracy and richness of information delivery. These advantages make VMS trailers the core infrastructure for real-time safety control in modern intelligent transportation systems.
From “passive information” to “active intervention”, VMS trailer is upgrading from a single transportation facility to a core node of intelligent transportation ecology. Its value is not only reflected in the reduction of accident rate, efficiency improvement and other visible indicators, but also through data-driven precision management, to promote traffic management to the “perceivable, predictable, controllable” high-level form of evolution. Under the background of accelerating the construction of smart cities, choosing a VMS trailer with both technological foresight and scenario suitability will be a key step to seize the high point of traffic management efficiency.
