An assessment of LTE-V2X (PC5) and 802.11p direct communications technologies for improved road safety in the EU
This report by the 5G Automotive Alliance (5GAA) presents a quantitative analysis of the ability of Cooperative Intelligent Transport Systems using short-range ad hoc/direct communications to reduce the number of fatalities/serious injuries caused by motoring accidents in the EU. In this context, the study estimates the number of accidents avoided over time through the use of two short-range wireless technologies, 3GPP LTE-V2X (PC5) and IEEE 802.11p, examining their respective performance and projected take-up among road users. The modelling underlying this report has been peer-reviewed and validated by the technology and policy consultancy, Ricardo.
Specifically, two standardised C-ITS short-range technologies are compared for the purposes of this report, namely 3GPP LTE-V2X PC5 (also known as LTE side-link) and IEEE 802.11p (also known as DSRC or ITS-G5), both operating in the 5.9 GHz band for the provision of direct communications between road users. It should be noted that additional reductions in the number of fatalities and serious injuries are possible via longer-range C-ITS communications enabled through interactions with a LTE cellular network, but that these are not considered in this report. Hence, the analysis is limited to LTE-V2X (PC5) only, in comparison to 802.11p.
This study examines and compares two independent counter-factual scenarios: one where LTE-V2X (PC5) is the only deployed C-ITS technology, and the other where 802.11p is the only deployed C-ITS technology.
We consider, as a baseline, the existing and future projected statistics for road traffic fatalities and serious injuries in the EU. We then evaluate the reduction in the number of fatalities and serious injuries which may occur as a result of C-ITS direct communications between road users, by modelling:
- The expected take-up (penetration) of LTE-V2X (PC5) and 802.11p among road users in the EU over time (including vehicles, motorcycles, bicycles and pedestrians), and
- the radio link performance of LTE-V2X (PC5) and 802.11p in successfully delivering actionable warning messages between road users in a number of collision scenarios.
We identify the following conclusions and recommendations from the results of this report:
- The study indicates that LTE-V2X (PC5) outperforms 802.11p in reducing fatalities and serious injuries on the EU’s roads. This is due to a combination of the superior performance of LTE-V2X (PC5) at the radio link level for ad hoc/direct communications between road users, and the market led conditions which better favour the deployment of LTE-V2X in vehicles and in smartphones, and include a clear evolutionary path towards 5G-V2X. For these reasons, it is essential that EU regulations remain technology neutral and do not hinder the deployment of LTE-V2X (PC5) in favour of 802.11p for the provision of direct communications among vehicles and between vehicles and vulnerable road users.
- An absence of interoperability at radio link level between LTE-V2X (PC5) and 802.11p is unlikely to present a substantive barrier to the reduction of road accidents in the EU in the short to medium term. The relatively low penetration of C-ITS technologies in vehicles in the first half of the next decade (and perhaps even later) means that a vehicle equipped with LTE-V2X (PC5) or 802.11p is far more likely to collide with a vehicle that is not equipped with C-ITS technologies at all – indeed it is not until the middle of the next decade that penetration rates are expected to reach a level which results in significant impacts on accident rates. Any regulations which mandate LTE-V2X (PC5) to be backward interoperable with 802.11p will therefore have only a limited effect in the early years of deployment pre-2025. Such regulations may run the risk of unnecessarily distorting the market in favour of 802.11p, thereby obstructing the adoption of LTE-V2X (PC5) and resulting in greater road fatalities and injuries in the longer term.