From the press release:

    GAME OVERVIEW
    The introduction of SEGA Rally to the arcades in 1995 had the single biggest impact on the racing genre. Subsequent console rally games concentrated on a realistic simulation of the sport, but their popularity, reflected in sales, steadily dropped over the last decade. Now, SEGA Rally is back and set to reinvigorate the genre with the vital ingredients that many of the modern racers lack – fun, character and beauty, with few rally games able to match its unique and rewarding experience. Rally’s dead, long live SEGA Rally.

    DEFORMATION
    The all new SEGA Rally retains all the pedigree of the 1995 arcade classic, whilst using all the resources available in the cutting edge next-gen hardware. One major innovation in the game which until now, no developer has managed to achieve – straining even the considerable computing power available today – is proper deformable track surfaces.

    DEFORMABLE SURFACES, WHAT PLAYERS GET FROM IT.
    As with the original SEGA Rally arcade cabinet, in single player mode the new SEGA Rally is about racing successive laps of the track against a number of opponents. Although, this time as well as AI players, players can race each other online or head to head.

    As players race each successive lap in the game, they and their competitors churn and wear the track leaving a scrubbed or rutted track surface behind. Unlike other games which have tricked players into believing they’re cutting up the track with visual trickery, SEGA Rally really is deforming the surface and this will affect the gameplay in a number of ways.

    As well as learning the race tracks to gain split-second advantages, players will start to see, hear and feel nuances in taking one racing line or another. For example, players might see a contour made by another car through some gravel, which if they follow will help them gain speed, whereas if they take a fresh route through the gravel it could potentially slow them down. It’s these gameplay elements that give extra depth, is what players expect from a next-gen console and is something no game has done before.

    HOW DOES IT WORK?
    Most games use a 1 metre polygon grid to drive upon, but that was never going to work for the level of details aimed for in SEGA Rally. Because of this, the entire drivable surface of every track within SEGA Rally is modelled at the massively high detail of 6 centimetres for every single polygon – that’s 17 times more detail and means that each tyre of each Rally car interacts with up to 12 polygons at any time.

    Importantly, the physics engine powering SEGA Rally also runs the detail at a high frame-rate, reacting to every bump in the highly detailed scenery. For every surface, there are a number of characteristics – in addition to the normal static and dynamic slip components SEGA Racing Studio has modelled wear rate and how ruts form for every polygon, how the friction changes as players dig down into the surface, and the profile of the debris which tyres leave as they churn each surface up. SEGA Racing Studio are even able to model the higher grip levels expected on tarmac as traffic lays down rubber – and that means real live racing lines forming that can and must be reacted to as in a real race.

    From a graphical point of view, as well as deforming the polygon surface of the track, multiple materials with specular lighting and bump mapping are blended per-pixel in real time, both along the length and into the surface of the track, as detailed in the screens shots provided.