GEOLOGIC HISTORY SHAPED RACING AT ROAD ATLANTA
are present in the area of Road Atlanta. However, the most abundant of these soil types are the Gwinnett clay loam and the Musella cobbly clay loam (Natural Resources Conservation Service, 2016). These soil units typically exhibit surface slopes of 25% and 35 %. Ironically, these soil units at Road Atlanta are considered to be a moderate to severe erosion hazard for roads, and therefore are moderately to poorly suited for road construction (NRCS, 2016).
Geology at 130 MPH
Uplifted and deformed by meta- morphism from mountain building and then weathered by the forces of nature, the 12 turns on 2.54 miles of racetrack have been shaped by the geologic history of the region into what Road and Track called “the most challenging racetrack in the world.” Typically, turns and other track fea- tures are named or numbered. Figure 1 shows that Road Atlanta has twelve numbered turns that are numbered in sequence from the starting line to the finish line. Seth Thomas’ blog, author of Axis of Oversteer, helps navigate through the braking zones and apexes of each of these turns (or groups of turns) as the regional geologic fea- tures shaped by uplift and erosion are illustrated.
Front Straight: This is where the paddock, staging area, and the start- ing line for races at Road Atlanta are located, facing southeast. Road Atlanta has a “rolling start” where the race cars are led by a pace car around the track until the starting line, when the pace car peels off and the race cars apply throttle and the race begins! Because it is a rolling start, front- straight speeds from Turn 12 to Turn 1 can be in excess of 120 mph. The sounds of high revving engines on the Front Straight can be felt throughout the grandstand as the sound fills the air while drivers battle to overtake one another before the braking zone for Turn 1. Sitting on the overburden of weathered mica schist, the iron oxide rich red clay can be seen on both sides of the race track that is not paved near the braking zone for Turn 1. This area of generally flat topography was formed by erosion from Copper Creek to the southeast with likely minor grading needed during construction. At the end of the Front Straight in the braking zone for Turn 1, glowing red brake rotors are visible as drivers
balance their race cars into the turn, preparing for the elevation changes of the next several turns.
Turns 1 through 4: Turn 1 of the track is a right hand turn with uphill and downhill elevation changes that continue through Turns 2, 3, and 4. The braking zones in these turns also have a variety of uphill and downhill elevation changes that reflect the undulating crystalline bedrock that has been shaped by the metamorpho- sis of mountain building from shale to schist. The elevation changes and varying speeds can leave a race car in the same gear or “grabbing” the bottom of higher gears which has the high engine revolutions per minute (rpm or revs) to the low engine revs as the drivers cycle through the gears, trying to balance the race cars to carry as much momentum as possible into and through The Esses.
The Esses: The most well-known of the turns at Road Atlanta, is a series of three turns that consist of more downhill, then uphill, elevation changes. Looking southwest toward Turn 5 (Figure 5), Spectator Hill (a sloping grassy hill) is visible. The red clay (weathered iron oxide from a biotite mica schist) is visible on both sides of the race track, while the elevation changes are due to the undulating crystalline bedrock that has produced the rolling topography of the Piedmont Region. The Esses are typically raced in the same gear where engine revs are high as drivers negotiate this series of turns, steering with the throttles while trying to keep momentum into Turn 5.
around from the straight, then using throttle to gain exit speed from Turn 7, now racing north and into the Back Straight (Figure 6).Turns 5 through 8 offer little elevation change due to a landform that has been weathered by Copper Creek to the south, with the creek bed seeming to almost mimic these series of turns. The braking zones in these series of turns are short and engine revs are high and loud, as drivers try to carry as much speed as possible by the end of Turn 8 towards the Back Straight.
The Back Straight: As shown on Figure 6, after exiting Turn 8 there is a downward straight racing north and at speeds upwards of 140 mph, and even 160 mph for some of the more powerful cars! This is where some very exciting passing, over-taking, and hard-fought battles to win take place! Race cars are almost a blur and high revving engines burn through gears as the drivers race towards the end of the track. The Back Straight is situated on the land which has been weathered on the west by Copper Creek creating a relatively flat sec- tion of racetrack before the braking zone. This is the braking zone where the smell of over-heated brake pads is in the air and brake rotors glow red from the friction of slowing a 160 mph race car from full throttle into a sharp left-hand turn…Turn 10A.
Figure 6 - Back Straight Figure 5 - The Esses
Turns 5 through 8: The entry to Turn 5 is slightly uphill followed by a straight allowing for acceleration, racing south with braking zones into Turn 6, then into Turn 7. These turns represent a 180-degree turn-
Turns 10A and 10B: These turns consist of a left and then right turn that set up some big elevation changes toward the end of the track. If a race car is unable to brake effectively, is unbalanced, or suffering from under- steer, there are gravel run-offs at Turns 10A and 10B to safely slow a rocketing race car! A race car rocket- ing off course here is quite a sight… the driver still fighting for control as the race car leaves the course and
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56
