Speed Limit Information Function (SLIF) Testing

Efficient solution for validating EU regulated Speed Limit Information Function (SLIF) and Intelligent Speed Assist (ISA)

EU-Compliant: Tailored to meet SLIF and ISA regulations
Time-Saving: Quick setup and early stop feature minimise test distances and time.
Seamless Integration: Compatible with video and CAN systems.
Real-time Data: Live monitoring of test compliance with True Positive Distance.

Test Your SLIF System with VBOX Precision

VBOX Automotive offers a bespoke solution for validating Speed Limit Information Function (SLIF) and Intelligent Speed Assist (ISA) systems, now mandatory under EU regulations. This innovative setup combines the VBOX Touch, SLIF test app, and Event Marker Box to streamline SLIF testing while ensuring accurate and efficient data collection.

The SLIF App records distance data, road and light conditions, and OK/NOK inputs for speed sign accuracy. Engineers can log these manually using the touch display or the Event Marker Box, which features one button to confirm matching speeds and another to log specific events for post-analysis. This enables precise, actionable insights into SLIF performance.

Real-time data monitoring on the VBOX Touch screen includes measuring True Positive Distance, allowing for early test completion if results remain within tolerance. This reduces driving requirements from 400 to 300 km, saving time and resources while improving testing efficiency.

For detailed analysis and post-processing, the VBOX Touch can be synchronized with a VBOX HD2 unit, linking video footage with recorded test events for deeper insights.

Standards and Regulations Overview

Under EU Regulation 2019/2144, Intelligent Speed Assistance (ISA) became mandatory for all new vehicles from July 2024. From 2026, it will also form part of the new Euro NCAP Safe Driving Vehicle Assistance Protocol.

What is SLIF?

The Speed Limit Information Function (SLIF) is a mandatory component of Intelligent Speed Assistance (ISA) systems. It uses cameras or map data to inform drivers of the current speed limit.

SLIF Validation

The validation of SLIF within ISA systems is specified in Commission Delegated Regulation (EU) 2021/1958. To ensure compliance, engineers must validate SLIF systems by logging inconsistencies between the vehicle’s speed limit display and actual speed limits over a minimum of 300 km. This testing must be conducted across a variety of road types and under different lighting conditions.

Key Features

Log Driving Metrics

Log and toggle road type and light conditions via the VBOX Touch app, ensuring complete data capture across a range of variables.

True Positive Distance (TP_D)

Automatically calculates TP_D, measuring the accuracy of vehicle display against road signage, ensuring precise compliance evaluations.

Early Stop Functionality

Reduce test-driving distance from 400 km to 300 km if TP_D accuracy stays within +/-5% over the final 50 km, saving time and resources.

Video Integration

For in-depth analysis and post-processing review of event markers, the VBOX Touch can synchronise with a VBOX HD2 unit, linking video footage with data events. This is particularly useful for identifying and reviewing instances where signage was misread or unrecognised.

SLIF Event Marker Box

Manual buttons to log key events and confirm matched speeds, providing actionable insights and simplifying result analysis.

CAN Output

CAN output from the VBOX Touch enables seamless integration with data loggers or other equipment within a broader test setup.

It can also be used to overlay key data metrics, such as TP_D or OK/NOK states, onto VBOX Video HD2 footage.

Testing Equipment

An ideal SLIF test setup consists of a VBOX Touch, an Event Marker Box and a VBOX HD2 Video unit, with the camera positioned facing the road and the dashboard with SLIF display.

A VBOX Touch running the Speed Limit Information Function (SLIF) Application logs distance data, sign recognition inputs (OK/NOK) and TP_D (% of the Total Distance where display and road signs match).

The Event Marker Box (RLACS348) is an alternative OK/NOK option and, in addition, triggers the events for review in post process.

GNSS and SLIF test data is synchronised to the VBOX HD2 video footage for easy post process analysis in VBOX Test Suite. All testing channels are also output over CAN, for use in external loggers.

VBOX Touch showing live results during a SLIF validation test: You can see that 106.19 km were driven on inter-urban roads under cloudy daylight conditions, with the speed displayed on the dashboard matching the road signs 96.68% of the time.