Indy 500: Yellow Caution Periods
Pack-Up Rule Since 1979
The "pack-up" rule, in which the pace car leads the field during yellow flag conditions, was not used at the Speedway until 1979. From 1936-1971, if a yellow situation arose, rules stated that drivers were to slow down and hold positions. The Speedway felt that drivers who were able to build up a large lead under green should not be penalized if the caution came out and the field was bunched up. In those cases, the yellow light could come on at any time, and could revert back to green at any time also. It was not necessary for the leader to be at the starter's stand in order to go back to green light conditions. Neither was it neccessary for the drivers to cross the start/finish line and "accept" the yellow before pitting. It was common for the green light to be turned back on at arbitrary times, without regard to the leader's position on the track. Yellow light periods typically could be very short, because full laps under the yellow were not necessary. Sometimes the yellow light condition lasted less than a lap, and the green was back on after only a half a minute or so if the situation was deemed safe.
Many drivers and crews, however, found loopholes in the old system, and were commonly able to make up several seconds without officials being aware. From 1972-1978, the "P.A.C.E.R." number board system was utilized. Around the track several number message boards were placed, recording the number of seconds between the cars. The object was to keep the numbers constant around the track. For example, if the caution began, and a car's interval was 5 seconds behind the car in front of him, the driver had to maintain 5 seconds around the track. If the next board stated 4 seconds, the driver was going too fast, and needed to slow down a little. If the next board said 6 seconds, the driver was lagging behind, and needed to speed up slightly. The boards even had three additional small lights, which were for "fine-tuning" and represented fractions of second. By 1978, all other Indy style races and all other American oval track races utilized a pace car for caution periods, packing up the field with the pace car leading the race leader. For safety sake, most drivers preferred the pack-up rule, figuring it would work for them just as many times as it would work against them. Safety crews also preferred the pack-up rule, since it would concentrate the race traffic into one pack rather than having cars spread out all over the track. This would allow them to work on cleaning up crashes, debris, etc., with a clear track, and longer time gaps between cars passing through the work zone.
The Speedway first utilized the pace car during caution periods in 1979. The celebrity driver who drove the pace car at the beginning of the race, however, was replaced by an experienced race official. In 1988, however, Chuck Yeager the celebrity driver had to pull back out and pace the first caution, as the regular offical at the time, Don Bailey, was not in the car yet. In many cases, the pace car used at the beginning of the race for the pace laps was not necessarily the same car used for caution periods during the race. During the pace laps, an "auxiliary" pace car might be stationed at the end of the pit road, ready for action. If by chance, the caution came out on the first lap, this pace car was ready to enter the track immediately, without having to wait to change drivers. The 1988 race also saw another first, in that the race finished under caution for a reason other than rain. On lap 198, Michael Andretti's car lost a piece of bodywork, and the pace car picked up the field with just over two laps to go. Cleanup could not be completed in time, and the pace car led Rick Mears across the finish line.
From 1979 until 1991, rules for pitting during cautions were also different. In those years, drivers could pit at any time, regardless of any yellow flag condition. It was very common for leaders to pit immediately as the caution came out, in order to take maximum advantage of track position. However, it was found to be quite a dangerous situation for both drivers and crews. According to the rules, positions basicially are frozen at the onset of the caution, but too many times, drivers raced to get into the pit area, which at the time, had no speed limit. Drivers could unjustly make up time on the field by speeding through the pits faster than they could packed up behind the pace car. Through 1988, the pit area was concrete, and very rough. Speeds in the pit area were kept down because of the bumpy surface. Beginning in 1989, however, the pits were repaved in asphalt, and drivers took advantage of the smooth surface, driving much faster through the pits, creating a potentially dangerous situation. Starting in 1992, drivers were required to pack-up behind the pace car before they were allowed to pit. At the onset of the caution, the pits were immediately closed (unless a car was already in the pits). Drivers could not pit at that time without penalty. As soon as the field was collected by the pace car, usually the first time by, the field could pit. The 1992 race was also the first year that a speed limit was implemented in the pit area to match the pace on the track during the yellow (100 mph at that time). The pit road speed limit was primarily for safety reasons, but also to prevent drivers from gaining time on the pace car (which stays out on the track) by driving faster than it in the pits, as they had begun to do.
In 1981, under the relatively new pack-up rule, a controversey erupted when leader Bobby Unser and second place Mario Andretti exited the pits. As the two cars re-entered the racing surface, they were beside the field as it went by behind the pace car. Unser passed numerous cars, allof which were not on the lead lap, as he assumed his position at the head of the field. Andretti passed some cars himself, and blended in amongst the lap cars. Unser went on to win, and Andretti finished second. When official results were posted the following day, Unser was penalized for passing the cars under caution, and Andretti was declared the winner. After several months of litigation and hearings, Unser was restored the win, and the rules for blending into the field were clarified.
In 1995, the pace car was the focus of another significant controversey. With ten laps to go, the pace car was leading Scott Goodyear back to the green flag. Goodyear lagged behind the pace car on the backstrech in order to get a jump on the rest of the field. However, in turn four, Goodyear blew by the pace car, as it had not reached the pit entrance yet, and the yellow light was still illuminated. Goodyear was penalized for passing the pace car. After a protest, some believed that the pace car was not leading the field back to the green fast enough, however scoring transponders did not support that theory. In an effort to prevent a similiar incident, in 2000, the rules for restarts were slightly changed. Instead of having the pace car bring the field down for the green flag, and pull off in turn four, it will now pull off the track at the end of the mainstrech. After a "one-to-go" signal is made from the starter's stand, the pace car pulls onto the warm-up lap in turn one. From that point on, the race leader would be responsible for pacing the restart, and it would prevent any incidents of the pace car affecting the race.
In 2001, a new rule was implemented for Indianapolis, and for all IRL events. Under the previous rules, the pace car would pick up the leader under yellow, and any cars ahead of the leader were allowed to pack up behind, potentially allowing them to make up nearly a full lap. If the leader(s) entered the pit area, any lapped cars who remained on the track would, as a result, go by them, and at that point were required to stay behind the pace car. They would in fact lead the field, albiet at the tail end of the lead lap, or numerous laps down. The lead lap cars in that case would actually line up single-file behind the lapped cars, and the overall leader of the race might be several cars deep in the restart order. Starting in 2001, if any lapped cars were ahead of the race leader behind the pace car, the were allowed to go around the pace car and make up that lap. As soon as the pace car pulled off the track for the "one-to-go" signal before green came back out, the lapped cars ahead of the leader then could, albiet cautiously, go by the pace car and catch up to the rear of the field, thus making up one lap. This practice was applauded by competitors and officials, as it prevented lapped cars from interferring with the leaders on a restart, and allowed for the natural progression of making up a lap if the leader had pitted, something that would have happened under green. The drawback, and the accepted check-and-balance, for the lapped cars is that they must stay on the track during the yellow, and can not pit. Otherwise they will lose their track position, and not be allowed to make up the lap.
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1972 5 yellows for 22 laps 29-31 debris on track 57-62 Mike Mosley crashed on frontstrech 145-150 Lee Kunzman crashed in turn 2 172-175 Debris on track 193-195 Mike Hiss spun in turn 2 |
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1973 Race held over three days Mon 5/28 Lap 1- Salt Walther crashed on the mainstrech at the start, 12 cars involved; race red flagged; start aborted Tue 5/29 Parade Lap- Start red flagged due to rain Wed 5/30 Lap 3 Peter Revson crashed in turn 3 Lap 58 Swede Savage crashed at exit of turn 4; fire truck hit crew memeber in pit area; race red flagged for over an hour Lap 129-133 Rain; race red flagged and ended after 133 laps |
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1974 7 yellows for 34:02 Lap 60 Lap 85 Jan Opperman spun in north shortchute Lap 115 Jerry Karl crashed in turn 3 Lap 183 Lloyd Ruby out of fuel Race red flagged for fans over the fence during Rutherford's cool-down lap |
197545-49 Mike Hiss crashed in turn 3 68-71 Mario Andretti spun on backstrech 97-101 Al Unser stalled, towed in 127-141 Tom Snevea crashed in turn 2 170-175 Gary Bettenhausen lost wheel; rain; race ended after 175 laps due to rain |
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1976 6 for 21 laps 4-6 Dick Simon stalled 10-13 Roger McCluskey crashed in turn 3 14-16 Debris 60-64 Johnny Parsons lost wheel 91-94 Jerry Grant stalled 100-103 Rain; race red flagged at lap 103 and eventually ended due to rain Race results reverted back to completion of lap 102 |
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1977 5 for 22 laps 36-44 (15:51) Lloyd Ruby crashed 49-51 (4:46) Eldon Rasmussen spun 69-72 (4:29) George Snider stalled, towed in 159-160 (3:15) Pancho Carter stalled, towed in 163-166 (8:37) Johnny Parsons stalled, towed in |
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1978 6 for 23 laps 2-4 Sheldon Kinser stalled, towed in 9-11 Kinser tow-in 26-31 Spike Gehlhausen crashed 48-51 Debris on track 84-85 Debris on track 114-118 Mears & Tom Bigelow tow-in |
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1979 6 for 32 laps 28-31 Cliff Hucul stalled, towed in 43-48 Sheldon Kinser stalled, towed in 94-98 Dickson stalled, towed in 103-107 Phil Threshie stalled, tow-in 156-162 Larry Rice crashed 191-195 Tom Sneva crashed |
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1980 13 for 65 laps 4-6 Larry Cannon stopped in turn 1, towed in 10-18 Dick Ferguson, Bill Whittington crashed in turn 2 21-24 Spike Gelhausen crahsed in turn 1 30-33 Tom Bagley stopped on backstretch 45-49 Johnny Parsons stopped in turn 1 57-62 Roger Rager, Jim McElreath crashed in south chute 72-75 Mario Andretti stopped on backstretch 85-90 Don Whittington spun in turn 4 118-124 Dick Simon lost front wheel 132-137 Jerry Sneva crashed in turn 1 142-146 Dennis Firestone stopped on backstretch 157-159 Debris 177-179 A.J. Foyt, stopped in turn 3 |
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1981 11 for 69 laps (1 hr, 42 min, 8 sec) 5-7 Debris 26-29 Rutherford, stalled backstretch 33-43 D. Whittington, accident backstretch 67-81 Ongais, accident T3 130-136 Halsmer, accident T3 140-144 Garza, accident north short chute 146-151 Smiley, accident T3 152-156 B. Whittington, stalled backstretch 162-165 Bigelow, stalled T1 180-184 Foyt, stalled backstretch 185-188 Debris |
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1982 6 for 41 laps Start: Aborted and red flagged due to crash involving Kevin Cogan, Mario Andretti, A.J. Foyt, Roger Mears, Dale Whittington on frontstrech 40-45 Tony Bettenhausen crashed on front strech 63-70 Danny Ongias, Jerry Sneva crashed in turn 2 96-102 George Snider stalled 132-135 Johnny Parsons spun in turn 2 138-141 Johnny Parsons stalled in turn 3 154-158 Danny Sullivan crashed in turn 3 |
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1983 5 for 30 laps 28-32 Patrick Bedard crashed in turn 4 45-51 Roger Mears crashed in turn 1 93-99 Mario Andretti, Johnny Parson crashed in turn 1 157-160 Bill Whittington stalled, towed in 171-176 Mike Mosely crashed in south shortchute |
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1984 5 for 33 laps 48-53 Spike Gehlausen spun 59-68 Patrick Bedard crashed in turn 4 107-114 Gordon Johncock crashed in pit entrance 154-158 Roberto Guerrero spun 163-167 Scott Brayton stalled, towed in |
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1985 8 for 41 laps 15-18 George Snider blown engine 22-28 Scott Brayton oil leak 74-77 Derek Daly stalled on track, towed in 120-122 Danny Sullivan spun in south shortchute 123-134 Tom Sneva, Rich Vogler crashed in turn 1 146-149 Danny Ongias stalled, towed in 170-175 John Paul, Jr. crashed 192-196 Bill Whittington crashed in turn 4 |
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1986 6 for 34 laps Pace lap (red flag) Tom Sneva crashed in turn 2; officials replaced 3 gallons to each pit area fuel tank 15-19 Mario Andretti stalled in turn 3 52-56 Debris in turn 1 102-106 Johnny Parsons crashed on backstrech 136-141 Rich Vogler crashed in turn 3 166-169 Roberto Moreno stalled in turn 3 195-198 Arie Luyendyk crashed in turn 4 |
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1987 10 for 51 laps 1-5 Josele Garza, Pancho Carter crashed in turn 1 27-33 Ludwig Heimrath, Jr. spun, lost wheel in turn 4 39-42 Debris 62-67 Debris 81-84 Danny Sullivan spun in turn 4 96-101 Dick Simon ran out of fuel on backstrech, towed in 131-134 Tony Bettenhausen lost wheel in turn 3; Roberto Guerrero hit wheel, it struck and killed spectator in northchute 150-158 Tom Sneva crashed in turn 3 162-166 Fabrizio Barbazza spun in turn 4 192-196 Mario Andretti stalled in turn 4, towed in |
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1988 14 for 68 laps 1-5 Roberto Guerrero, Scott Brayton, Tony Bettenhausen crashed in turn 2 34-39 Tom Sneva crashed in pit entrance 58-63 A.J. Foyt crashed in turn 2 64-70 Ludwig Heimrath, Jr. hit from behind by Arie Luyendyk and crashed in turn 4 82-88 Steve Chassey, Rich Vogler crashed in turn 4 93-95 Debris 102-106 Danny Sullivan crashed in turn 1 109-111 Rick Mears, Al Unser, Sr. hit a rabbit on backstrech 117-120 Johnny Rutherford crashed in turn 1 140-145 Mario Andretti stalled, towed in 160-163 Tero Palmroth stalled, towed in 167-170 Rocky Moran blown engine in turn 1 175-179 Rich Vogler crashed in turn 3 198-200 Debris, Michael Andretti lost piece of bodywork; fire truck crew dropped can lid (Race ended under caution) |
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1989 7 for 43 laps 5-14 Kevin Cogan crash in turn 4 61-65 Bobby Rahal stalled turn 3, towed in 129-131 Arie Luyendyk blown engine 139-149 Jim Crawford stalled, towed in 162-166 Michael Andretti blown engine 181-186 Tero Palmroth lost wheel in turn 4 199-200 Al Unser, Jr. crashed in turn 3 (Race ended under caution) |
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1990 4 for 26 laps 20-25 Danny Sullivan crashed in turn 1 45-51 Tony Bettenhausen stalled, towed in 63-69 Pancho Carter crashed in turn 4 141-146 John Andretti brushed wall in turn four, then spun in turn 1 |
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1991 7 for 30 laps 1-3 Buddy Lazier crashed, Gary Bettenhausen spun in turn 1 20-33 Eddie Cheever stalled in turn 4 25-33 Roberto Guerrero, Kevin Cogan, A.J. Foyt crashed in turn 2 84-89 Tero Palmroth stalled with car on fire on backstrech 148-153 Scott Brayton blown engine 184-186 Danny Sullivan stalled, broken turbocharger, on frontstrech 191-194 Mario Andretti stalled in turn 4 |
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1992 13 for 85 laps Pace Lap Roberto Guerrero crashed on backstrech, Felippe Gache spun in turn 4 6-10 Eric Bachelart blown engine 12-20 Tom Sneva crashed in turn 4 62-66 Gordon Johncock blown engine 67-75 Felippe Gache, Stan Fox crashed in turn 1 on the restart 76-83 Jim Crawford, Rick Mears, Emerson Fittipaldi crashed in turn 1 on restart 84-89 Mario Andretti crashed in turn 4 on the restart 94-96 Scott Brayton blown engine 97-102 Paul Tracy blown engine on the restart 103-109 Brian Bonner crashed in turn 4 on the restart 115-122 Jeff Andretti, Gary Bettenhausen crashed in turn 2 137-143 Arie Luyendyk crashed in turn 4 150-155 Buddy Lazier blown engine 189-193 Michael Andretti stalled in turn 4 |
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1993 8 for 51 laps 16-20 Debris 30-37 Danny Sullivan crashed in turn 3 88-92 Debris 95-103 Paul Tracy crashed in turn 3 127-137 Jeff Andretti, Roberto Guerrero crashed in turn 3 168-173 Robby Gordon stalled 181-184 Lyn St. James stalled in turn 4 192-194 Nigel Mansell brushed wall, kept going |
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1994 7 for 43 laps 7-9 Dennis Vitolo spun in turn 4 21-27 Roberto Guerrero crashed in turn 2 30-40 Mike Groff, Dominic Dobson crashed in turn 1 92-100 Hideshi Matsuda, John Paul, Jr. crashed in turn 1; Dennis Vitolo, Nigel Mansell crashed in turn 3 warm up lane 137-138 Debris, turn 3 185-190 Emerson Fittipaldi crashed in turn 4, coasted down frontstrech 197-200 Stan Fox crashed in turn 1 (Race ended under caution) |
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1995 9 for 58 laps 1-9 Stan Fox, Eddie Cheever, Carlos Guerrero, Lyn St. James, Gil de Ferran crashed in turn 1 37-44 Debris 80-86 Scott Sharp crashed in turn 4 89-95 Stephan Johansson spun 123-126 Andre Ribiero stalled 138-141 Paul Tracy stalled 163-169 Davy Jones crashed in turn 2 171-176 Jimmy Vasser crashed in turn 3 185-190 Scott Pruett crashed on backstrech |
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1996 10 for 59 laps 2-4 Debris, turn 4 11-15 Paul Durant blown engine 17-19 Danny Ongias spun in turn 3 50-55 Johnny Parsons blown engine 70-74 Debris; Scott Harrington stalled, towed in 94-101 Brad Murphy crashed in turn 2 118-125 Fermin Velez blown engine 130-134 Mark Dismore blown engine 159-168 Scott Harrington, Lyn St. James crashed in turn 1 195-199 Scott Sharp crashed in turn 2 |
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1997 12 for 56 laps Pace Lap Affonso Giafonne, Kenny Brack, Stephan Gregorie crashed in turn 4 10-15 Claude Bourbonnais blown engine, Rain 15 Red Flag: Rain (Mon 5/26, race postponed until next day) 16-18 Restart Warm-up laps (Tue 5/27) 20-28 Robby Gordon stopped in turn 3 warm up lane with electrical fire 59-62 Jim Guthrie stalled on frontstrech, towed in 94-99 Eliseo Salazar stalled in turn 1, towed in 114-123 Billy Roe, Paul Durant crashed in turn 3 138-142 Dr. Jack Miller crashed on backstrech 165-169 Tyce Carlson spun in turn 1 189-193 Steve Kinser, Lyn St. James crashed in turn 4 & frontstrech 196-197 Debris 199 Tony Stewart brushed wall in turn 4, kept going (Yellow light remained on inadvertantly during most of lap 200) |
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1998 12 for 41 laps
1-3 J.J. Yeley spun in turn 1
24-26 Tony Stewart blown engine
36-38 Donnie Beechler blown engine
47-48 Robbie Buhl stalled on backstrech
52-63 Multi-car crash in turn 3 involving:
Marco Greco, Sam Schmidt, Stan Wattles, Roberto Guerrero, Jim Guthrie, Mark Dismore, Billy Roe
95-99 Jimmy Kite stalled, towed in
124-127 Dr. Jack Miller stalled, towed in
134-135 Billy Boat stalled on backstrech, towed in
155-156 Arie Luyendyk stalled in turn 1, towed in
178-179 Stephan Gregorie crashed in turn 4
182 Hewitt spin T1
193-194 Greco lost engine
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1999 8 for 42 laps 9-14 Eliseo Salazar crashed in turn 2 35-39 Hideshi Matsuda stalled 63-68 Sam Schmidt crashed in turn 1 93-98 Steve Knapp spun in turn 2 102-105 Scott Goodyear blown engine 118-124 Arie Luyendyk crashed in turn 3 162-164 Jimmy Kite stalled 169-173 Mark Dismore crashed in turn 2 |
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2000 7 for 39 laps 66-70 Greg Ray crashed in turn 2 74-84 Lyn St. James & Sarah Fisher crashed in turn 4 99-102 Debris 127-130 Oil on track 144-150 Greg Ray crashed in turn 2 158-161 Sam Hornish, Jr. crashed in turn 2 174-177 Oil on track |
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2001 8 for 56 laps 1-5 Scott Sharp crashed in south short chute 8-16 Sarah Fisher & Scott Goodyear crashed in turn 2 18-21 Sam Hornish, Jr. spun, Al Unser, Jr. crashed in turn 4 90-95 Track inspection, oil on track 107-118 Rain 134-138 Cory Witherill crashed in turn 4 148-155 Track inspection, oil on track, Jon Herb crashed in turn 1, Rain 155 Red Flag: Rain (16 min. 34 sec.) 156-157 Restart warm up laps 166-170 Robbie Buhl crashed in turn 2 |
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2002 5 for 35 laps 30-36 Greg Ray crashed in turn 1 79-87 Debris on track 90-98 Tony Kanaan, Rick Treadway crashed in turn 3 173-180 Tomas Scheckter crashed in turn 4 199-200 Buddy Lazier & Laurent Redon crashed in turn 2 (Race ended under caution) |
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2003 9 for 49 laps 9-13 Billy Boat slow, smoking in turn 2 16-21 Sarah Fisher blew motor, crashed in turn 3 53-60 Robbie Buhl spun at the pit exit warm-up lane 62-65 Richie Hearn, Jaques Lazier crashed in turn 2 104-108 Jimmy Vasser slow, smoking on the backstrech 127-133 Airton Dare crashed in turn 2 172-174 Robby Gordon stalled in turn 4, towed to pits 182-185 Scott Sharp crashed in turn 1 187-193 Dan Wheldon crashed in turn 4; then Scott Dixon crashed on frontstrech |
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2004 8 for 56 laps 11-15 A.J. Foyt IV crashed in turn 1 22-27 Rain 27 Red Flag for rain 28-29 Restart warm-up laps 56-61 Larry Foyt crashed in turn 2 63-69 Mark Taylor and Ed Carpenter crashed in turn 3 95-102 P.J. Jones crashed on backstrech 106-115 Darren Manning, Sam Hornish Jr. and Greg Ray crashed at entrance to pits 132-136 Marty Roth crashed in exit of turn 4 174-180 Rain; race ended after 180 laps due to rain |
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2005 8 for 46 laps 18-24 Larry Foyt crashed in turn 1 77-86 A.J. Foyt, IV touched wheels with Bruno Junqueira and Junqueira crashed in turn 2 114-119 Scott Dixon and Richie Hearn crashed in turn 1 147-154 Sam Hornish, Jr. crashed in turn 1 155-161 Danica Patrick spun, then Tomas Scheckter, Tomas Enge, and Jeff Bucknam crashed in the north short chute 171-173 Car of Roger Yasukawa smoking 187-189 Kosuke Matsuura crashed in turn 4 199-200 Sebastien Bourdais crashed in turn 3 (Race ended under caution) |
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2006 5 for 44 laps 2-6 #91 Chesson, #92 Bucknum crashed in turn 2 67-75 #2 Scheckter crashed exiting turn 4 111-122 #3 Castroneves and #15 Rice crashed in turn 4 149-161 #31 Unser, Jr. crashed in northchute 191-195 #14 Giaffone brushed wall in turn 2 |
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2007 11 for 55 laps 11-15 Debris (#33 John Andretti lost mirror) 38-43 #77 Moreno crashed in turn 1 52-59 #19 Herb crashed in turn 2 66-70 #23 Duno crashed in turn 1 99-106 #33 John Andretti crashed in turn 2 108-111 #31 Giebler crashed in turn 1 112-113 Rain RED FLAG AT LAP 113 114-115 Resstart warm up laps 151-156 #25 Roth crashed in turn 1 157-161 #11 Kanaan spun and #21 J. Lazier crashed in turn 4 163-166 #10 Wheldon, #15 Rice, #20 Carpenter, #26 Marco Andretti crashed on the brackstrech RACE ENDED AFTER 166 LAPS DUE TO RAIN |
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2008 8 for 69 laps 8-16 Debris (#18 Bruno Junquiera lost mirror) 37-44 #06 Rahal crashed in turn 4 61-71 #25 Roth crashed in turn 4 80-90 #34 Camara crashed in southchute 106-116 #11 Kanaan and #67 Fisher crashed in turn 3; Simmons crashed frontstrech 133-138 #02 Wilson crashed in southchute 153-158 #16 Lloyd crashed in pit entrance 169-175 #23 Duno spun in turn 3 |
Total Yellow Periods (1936-1978)
1936:
1937:
1938:
1939:
1940:
1941:
1946: 34 minutes, 31 seconds
1947: 21 minutes, 58 seconds
1948: 10 minutes, 40 seconds
1949: 8 minutes, 30 seconds
1950: 8 minutes, 30 seconds
1951:
1952:
1953: 9 minutes, 8 seconds
1954: 21 minutes, 9 seconds
1955: 30 minutes, 25 seconds
1956: 1 hour, 11 minutes, 15 seconds
1957: 31 minutes, 41 seconds
1958: 36 minutes, 38 seconds
1959: 43 minutes, 17 seconds
1960: 29 minutes, 7 seconds
1961: 33 minutes, 2 seconds
1962: 38 minutes, 18 seconds
1963: 49 minutes
1964: 30 minutes, 17 seconds
1965: 11 minutes, 40 seconds
1966: 6 for 41 minutes
1967: 10 for 1 hour, 4 minutes (race red flagged; includes restart warm-up laps)
1968: 5 for 47 minutes
1969: 2 for 14 minutes
1970: 3 for 25 minutes, 15 seconds
1971: 4 for 53 minutes
1972: 5 for 20 minutes, 36 seconds
1973:
1974: 7 for 34 minutes, 2 seconds
1975: 5 for 34 laps
1976: 1 for 7 laps
1977: 5 for 22 laps
1978: 6 for 24 laps