Heavy Duty Trucking Logo
MenuMENU
SearchSEARCH

GiraffeG4 Sentinel Updates Low-Clearance Alert System

The GiraffeG4 low-clearance alert system has been upgraded and can alert drivers through in-cab fleet telematics screens about upcoming low bridges.

GiraffeG4 Sentinel Updates Low-Clearance Alert System

The GiraffeG4 Sentinel System, a two-part system featuring a Tracking App and a User App, is designed to alert drivers to low-clearance obstacles.

Photo: Giraffe G4 LLC

3 min to read


The original GiraffeG4 low-clearance alert system has been upgraded to the GiraffeG4 Sentinel System, a two-part system featuring a Tracking App and a User App.

Giraffe G4 LLC said drivers wanted the GiraffeG4 to warn them of a potential low-clearance hazard before they reached it. The company said fleets wanted to keep driver distraction to a minimum, so the fleet telematics screen had to be the hub for driver information.

Ad Loading...

Upgraded System

Using GiraffeG4's original weatherproof sound wave system for measuring clearance height, the new GiraffeG4 Sentinel was redesigned as a two-part system.

The Tracking App can pre-measure and GPS locate any potential low-clearance hazard, whether it's a bridge, trestle, parking garage, or tree, according to the company. That information is downloaded onto a database.

Starting the following day, the User App uses that recorded height and GPS data to alert a driver with an alarm and height sign, 200 yards before they reach the hazard ahead.

Ad Loading...

Integrating with Fleet Telematics

The company said its GiraffeG4 Sentinel System has been built to integrate smoothly into any fleet telematics system.

The GiraffeG4 Sentinel System, according to the company, is not a navigation tool. It is a safety tool that follows underneath the route the driver is on and provides an audible warning to a distracted, tired, or lost driver.

The GiraffeG4 Sentinel staff, the company said, has already pre-measured and GPS located all the potential low-clearance hazards in New York City; New Jersey; Chicago, Illinois; Milwaukee, Wisconsin; Connecticut, and Philadelphia, Pennsylvania.

Plus, the Sentinel User App has an audible alarm at the entrance to every parkway in New York, New Jersey, Connecticut, and Massachusetts where commercial vehicles are prohibited.

Original Idea

The original idea for the GiraffeG4 System came about when Frank Nugent saw a film crew measuring the distance to the ceiling with a laser to learn how much rope was needed to hang some curtains.

Ad Loading...

After college and before working in the film business as a production manager, Nugent drove a tractor-trailer for A&P Supermarkets delivering groceries all around New York City. He became familiar with the low-clearance hazards that subway trestles provided — the hard way. He hit one with his trailer.

Nugent enlisted his son to help develop the GiraffeG4 System. Neither was trained as electrical, mechanical, or sound engineers, so, they hired freelance engineers and did all the on-the-street testing themselves under the subway trestles and tunnels around New York City.

Measuring Methods

Laser measuring was the first attempt, the company said, but it wouldn't work outdoors in sunlight.

Insead, they turned to sound waves. Weatherproof and hardy, a sensor could send a signal up and back to a subway steel beam. Timing that trip could tell them the exact height of the low-clearance hazard.

Eighteen months and three U.S. patents later, according to the company, the GiraffeG4 System was ready to go. It was marketed to truckers and recreational vehicle drivers. Drivers could pull the tow vehicle up to the low-clearance hazard, measure it, and continue to measure as they travel under the hazard.

More Safety & Compliance

Man standing beside tractor-trailer in sepia tone with the words "Farewell CDL" superimposed on top
Driversby Jack RobertsJuly 1, 2026

Farewell, CDL: Why I'm Giving Up My Commercial Driver's License

After more than 20 years as a CDL holder, HDT Executive Editor Jack Roberts is letting his commercial license expire. Not because he wants to — but because trucking's nuclear verdict crisis has made the risks of public-road test drives too great for editors, manufacturers, and everyone involved.

Read More →
thermo king heavy duty trucking
SponsoredJuly 1, 2026

Enhance Fleet Performance with High-Efficiency Auxiliary Power Units

Drive sustainable cost savings while increasing driver comfort during short- and long-haul logistics operations.

Read More →
Maintenanceby Deborah LockridgeJune 23, 2026

Wabash Trailers Recalled for Improperly Installed Underride Guards

More than 900 Wabash dry van trailers may not comply with the Federal Motor Vehicle Safety Standard for rear impact guards.

Read More →
Ad Loading...
YouTube thumbnail with photo of K&B's Lance Evans with truck in the background and the words, Trucking's AI Wake-Up Call

Why K&B Trucking Is Embracing AI and Driver Safety Technology

Crunching data and embracing artificial intelligence are key in K&B Trucking's safety efforts, says the company's safety director.

Read More →
The Cyber Stop header showing an enforcement officer talking to a truck driver and a screen shot of the FMCSA's revoked ELDs list
Safety & Complianceby Ben WilkensJune 19, 2026

The Hidden Problem Behind FMCSA's ELD Revocations

NMFTA researchers say dozens of registered ELDs may be built on the same software platforms, allowing compliance and security concerns to persist even after individual devices are removed from the market.

Read More →
Illustration of inside truck cab with dashcam on window, definition of research, and ATRI logo

ATRI Wants Motor Carriers for Driver-Facing Camera Study

In this new study, the American Transportation Research Institute will explore how driver-facing cameras can impact safety and operational metrics in trucking fleets.

Read More →
Ad Loading...
Man seated in front of computer with inset of insights generated for a truck driver

Netradyne Intelligence Uses New AI Agents to Automate Response to In-Cab Camera Data

The company called the next-generation in-cab camera safety platform "a fundamental shift from systems that report on what happened to systems that actively drive what should happen next."

Read More →
Maintenanceby Deborah LockridgeJune 15, 2026

Mack, Volvo Issue ‘Do Not Drive’ Recall on Possible Wheel-Offs

Owners will be sent advance notice not to operate their affected vehicles until the remedy is performed.

Read More →
Fleetworth-Lytx integration.

Fleetworthy Integrates Lytx Video Snapshots into Safety+ Platform

A new Fleetworthy-Lytx integration gives fleet managers access to video context alongside safety event data, streamlining driver coaching and incident review.

Read More →
Ad Loading...
Podcast thumbnail illustration
Fleet ManagementJune 4, 2026

How Waste Connections is Using Data, Telematics, and AI

How do you manage and maintain more than 18,000 connected trucks? Data. Lots of it.

Read More →