These Traffic and Chase rules give detail to every possible aspect of overland travel, from random traffic generators to the reactions of other drivers, to common road hazards. Vehicles imply modern day transportation, but in pre-modern settings it also includes horses, carts, carriages, etc. With slight tweaking and common sense, certain parts of these rules may even be used to give additional flavor to pedestrian chases.
VEHICULAR MANEUVER DIFFICULTY TABLE Difficulty Level: DC Modifier
(base 10)
Driving at Speed Limit 0 Driving over speed limit/safe driving speed +1 per 5mph
No traffic -1
Light traffic (1-6 vehicles) +1
Medium Traffic +2
Heavy Traffic +3
Extreme Traffic +4
Attempting a turn traveling faster than vehicles top speed for degree of turn. Usually involves a “drift” or “power slide” maneuver
+1 per 2mph over turn top
speed Driving in reverse +1 per 5mph
Driving under fire +4
Driver distracted (talking on hand held phone, eating) +2 Recovering from loss of control (ignore 1 10mph increment
for every +1 of maneuverability, if the vehicle has negative maneuverability, add a 10mph increment for every –1)
+1 per 10mph
Vehicle traveling faster than 80% of listed top speed +3 Vehicle traveling more than 80 mph regardless of top speed
(Add or reduce 10mph to the 80 for every bonus or minus to maneuverability a vehicle possesses.)
+3 every 20mph over 80 (round
up) Making a full deceleration +1 Slamming on the brakes +3 Doing something crazy, like attempting a jump, driving
under a truck, driving in oncoming traffic or other insane stunt. (May be modified by circumstance at GM discretion)
+6
Recovering from a sideswipe or a ram from behind (either as attacker or target)
+2 Recovering from impact from side or behind greater than 10
degrees
(either as attacker or target) (receives additional +1 for every 10 degrees up to 90)
+3
Driving with flat tire (non steering tire)
(vehicles with more than 2 non steering tires reduce this penalty by half)
+2 difficulty (per flat tire) Driving with flat tire (steering) +3
Treaded vehicle -3
Driving blind +10
Extra actions w/ cybercontrols (Near Future+ settings only) -1/action DRIVING OFF-ROAD
Fairly flat field +2
Partially wooded, rocky, and/or hilly terrain +4 Densely wooded, very rocky, and/or steep hills +6 Flat, hard packed desert 0
Loose sand +3
High dunes, drifting sands +6
Off-road capable vehicles treat off-road conditions as having a 2 point lower modifier
Treaded vehicles treat off-road conditions as having a 4 point lower modifier
RANDOM TRAFFIC GENERATOR
1d10 # OF VEHICLES
1 Road Clear
2-6 Light Traffic 1d6 Vehicles
7-9 Medium Traffic 2d6 Vehicles
10 Heavy Traffic 3d6 Vehicles
Default is for Daytime, (normal hours 5-7AM, 9AM-3PM, and 6PM to 9PM)
Rush Hour (7AM-9AM and 4PM-6PM) doubles the number of vehicles rolled
Night time (9PM-12PM) 1/2 of the vehicles rolled (round down)
Late night/early morning (12pm-5am) 1/3 of vehicles rolled, (round down) High population Area = x2 Vehicles rolled
Rural Area = 1/2 vehicles rolled (round down)
Desolate area (interstates between cities, extreme back roads, etc...) = 1/4 vehicles rolled (round down)
Dirt Roads raise difficulty modifier level by 1
Road in severe disrepair raise difficulty modifier level by 2
Light rain, snow, = -10% of vehicles on road (round down), treat speed limit as if -10mph posted, increases difficulty modifier level by 1 Heavy Rain, Snow, Ice, fog, and Sandstorm = -50% of vehicles on road (round down), treat speed limit as if half posted, and Difficulty Modifier level raises by 2
For every 2 vehicles over 5 per lane in an increment, treat posted speed limit as being 10% lower in that lane
Roll on the table above once for traffic moving in your direction, and again for the traffic in the oncoming lanes.
The default is for a 4-lane road (2 lanes moving your direction, 2 lanes oncoming). For every additional lane add 1d6 vehicles,
Traffic Random Vehicle Generator:
1D10 VEHICLE
1-2 Motorcycle
2-3 Compact Car, Midsize, Car Sedan,
6 Luxury Vehicle, Sportscar
7-8 SUV, Pickup Truck, or Minivan
9 Large SUV, Van, or Light Truck
10 Semi Truck or Large RV
For the purposes of any situation where it would be required to represent the movement of vehicles in relation to stationary or slow moving objects/people the formula is simple. For every 1 mph an object, vehicle, or person is traveling, they move 1 yard. For instance, a vehicle moving at 20 mph can move 20 yards per 3 second turn.
TRAFFIC: Traffic is always assumed to be going the posted
speed limit (or the speed limit as modified by road, traffic, and weather conditions). Individual traffic however, may deviate by 1d10 mph over or under the posted speed limit for an addition realistic touch).
For every 5mph difference over the posted speed limit, drop the re- roll time by 1 round (3.3 seconds), to a minimum of 1 round. Meaning if you are going the posted speed limit of 40mph, then you only re-roll the traffic generator every 10 rounds (equal to 30 seconds game time). However, if you are doing 70 in a 40mph zone, then you re-roll traffic every 3 rounds (12 seconds). If you are doing 95 or more in a 40mph zone, you re-roll every round (3.3 seconds), the same as if you are doing 125mph in a 70mph zone.
MPH over posted speed re-roll times modified by speed MPH over posted speed re-roll times modified by speed Posted speed 10 rounds (30
seconds) +25 mph 5 rounds (15 seconds) +5 mph 9 rounds (27 seconds) +30 mph 4 rounds (12 seconds) +10 mph 8 rounds (24 seconds) +35 mph 3 rounds (9 seconds) +15 mph 7 rounds (21 seconds) +40 mph 2 rounds (6 seconds) + 20 mph 6 rounds (18 seconds) +50 mph 1 rounds (3 seconds) MPH to KM/H Simple Conversion 5 mph = ~10 km/h 10 mph = ~15 km/h 15 mph = ~25 km/h 20 mph = ~30 km/h 25 mph = ~40 km/h 30 mph = ~50 km/h 35 mph = ~55 km/h 40 mph = ~65 km/h 45 mph = ~70 km/h 50 mph = ~80 km/h 60 mph = ~100 km/h 70 mph = ~115 km/h 80 mph = ~130 km/h OTHER TRAFFIC AND ROAD RULES:
Random side street availability, for every traffic re-roll increment :
(Roll for traffic at each street only if characters are turning or that street has right of way)
Roll 1d6 CITY URBAN HIGHWAY RURAL HIGHWAY RURAL ROAD (50% CHANCE SIDE ROAD IS DIRT) 1 NO NO NO NO 2 1 NO NO NO
3-4 2 1 EXIT RAMP NO 1 ROAD
5 3 1 EXIT RAMP NO 2 ROADS
6 4 2 EXIT
RAMPS
1 EXIT RAMP 3 ROADS
CHASE POSITION: For every 10mph over the speed of traffic
an individual vehicle is traveling, it may pull ahead at 1 car length per round. For vehicles involved in a chase or race, this rule only counts towards vehicles moving at the posted (modified) speed limit.
Vehicles involved in a chase move relative to traffic, individual speed, acceleration, and other modifiers determine their position relative to each other.
ROUND BY ROUND
ACCELERATION: Roll a drive check, on a successful roll,
every point over the target difficulty allows you to accelerate 5mph. Failure of this roll indicates a character has become nervous or unsure, and decelerates by 5mph instead. Alternatively, at any time a character may opt to decelerate safely at up to half his listed deceleration.
Making a full deceleration requires a roll +1 difficulty higher than the standard for driving (with modifiers for speed, weather, road conditions and traffic included). Slamming on the brakes (x2 deceleration speed) incurs a +3 difficulty and also forces any vehicles behind you and within your threat range, to make an immediate maneuver roll with additional modifiers due to distance included.
THREAT RANGE: Threat range is the area behind a vehicle
where any other vehicle following is forced to make a maneuver check in case the vehicle ahead of them decelerates suddenly.
THREAT RANGE
Every ten mph a vehicle is traveling increases the threat range by 1 vehicle length
Vehicles in a threat range have their difficulty modifier increased by +3 (for the purposes of avoiding collision in case car ahead slams on brakes or decelerates suddenly) for every vehicle length they are nearer to the vehicle in front of them.
TURNING: This is the speed your vehicle must reduce to in order
to turn without penalty, for every point of maneuverability
bonus/penalty; you may increase/decrease this speed by 5 mph (for the purposes of this, count all 0's as being –10mph consecutively). If top speed is zero, the vehicle effectively comes to a complete stop.
TOP TURNING SPEED
Radius Top Speed Radius Top Speed
15 degree 70 mph 105 degree 10 mph 30 degree 60 mph 120 degree 0 45 degree 50 mph 135 degree 0 60 degree 40 mph 150 degree 0 75 degree 30 mph 165 degree 0 90 degree 20 mph 180 degree 0
Roll 1d10 on the following chart whenever an involved vehicle makes any maneuver that would cause a non-involved vehicle to react.
INTERSECTIONS: At every city or rural side street encountered
roll 1D10 (If you are currently on a main thoroughfare, re-roll a 3- 5 once and keep result.)
RANDOM INTERSECTION TABLE 1-2 Side streets have stop signs
3 You have stop sign
4-5 4-way stop sign
6-10 Stop light
For a stop light roll 1d6
1-3 green, 4 yellow, 5-6 red (if yellow it will change to red in 1d6/3 rounds (3-6 seconds)
For every 15 seconds it takes you to reach the intersection, there is a 25% chance a light will change color.
RANDOM ROAD OCCURRENCES
(roll once every ten increments of random traffic, only during actual chases, or alternatively, a GM may simply use these instances as a guide for adding flavor a chase)
1D100 RESULT
1-3 Driver ahead slams on brakes
4-10 Opening in traffic, Road clear ahead for 2 increments (comes in to play next increment)
11-20 Vehicles ahead of you are side by side and blocking you from passing
21-24 Opportunity for cinematic maneuver (ramp allowing for jump, vehicle with loose cargo, etc...) (comes into
play next increment)
25-29 As you move to pass a vehicle it suddenly swerves into your lane (18 difficulty to avoid
30-35 Traffic closes behind you, hindering pursuit for 2 increments
36-38 Animal, person runs out into road ahead of you (18 difficulty to avoid)
39-42 Vacant lot, open field on side of road 43-45 Something falls from a vehicle in front of you (20
difficulty to avoid)
46-50 Emergency vehicle, lights and siren on, pulls onto road ahead of you, moves 20mph faster than posted speed
limit, stays on road for 2d10 rounds
51-55 Collision between one or more vehicles in front of you (23 to avoid)
56-60 Road ends in a T-Junction (if on rural road, road becomes dead end, if on interstate, ignore and re-roll) 61-65 Road Damage (large potholes, etc..)
65-72 Road changes size (even larger, odd smaller), Roll 1D6/2 to determine additional lane increase/decrease.
Even numbers always result in the lanes distributed equally to both outbound and inbound lanes, if the roll is odd, the GM determines placement of the lane (if the
road gets smaller and decreases to 1 lane, the road becomes 1-way).
73-78 Oil, Ice (15 difficulty to keep control, or glass, nails, debris, etc.. (10% chance of blowout)
79-84 Sharp Curve ahead, increases difficulty modifier by one level.
85-87 Driver from side street runs light or stop sign (24 difficulty to avoid)
88-93 Traffic Jam ahead, all traffic comes to a complete stop 94-96 Oncoming traffic suddenly swerves into your lane
(difficulty 26 to avoid) 97-
100
Vehicle broken down in middle of the road
For every increment of random traffic rolled, there is a 10 percent chance of police presence
REACTIONS OF NON INVOLVED DRIVERS TO VEHICLES INVOLVED IN CHASE
1D10 REACTION RESULT
1 Driver panics, loses control of vehicle (roll on vehicle fumble table)
2 Driver not paying attention, cannot react or evade 3 Road Rage, driver purposely does whatever he can to hinder
involved vehicle, 20% chance he will join chase
4 Driver Speeds up
5-6 Driver slows down
7 Driver moves out of way violently, if driver is in outside lane he will move onto shoulder or sidewalk, if he is in inside lane he will move into oncoming traffic, if multiple lane, he will move
into adjoining lane regardless of traffic.
8 Driver slams on breaks
The GM should assign all primary vehicles (Character Vehicles, involved NPC vehicles, etc.) a quality rating.
VEHICLE QUALITY RATING
Breakdown chance is rolled once per day vehicle is used. There is ALWAYS at least a 1% chance of vehicle breakdown. For every 20% of SDP damage taken a vehicle drops one category and
must make an immediate breakdown chance roll.
Quality Rating Chance of breakdown per day
Last Legs 20%
Used and Abused 15%
Normal 10%
Maintained 5%
Showroom Quality 1%
Other quality rating modifiers
New vehicle (1 year old or less) - 10%
Used (2-10 years old) +5%
Well Used (11-20 years old) +10% Classic (21-30 years old) +15%
Antique (31+ years old) +20%
Standard Maintenance 0
Well Maintained -5%
Lovingly Maintained by Top Grade Professional mechanics -10%
No Maintenance +10%
In a crash, the vehicle skids its current speed in yards forward, hitting anything in the way (See impact rules). If the vehicle has not been trashed, the driver has to succeed at a Driving roll vs. Difficulty 20 to regain control in the following turn, -5 Difficulty per successive turn.
In a spin, an air vehicle plummets down 25m per turn. If this loss of altitude brings it to ground level, the vehicle is destroyed. As above, the pilot must succeed at a Piloting roll vs. Difficulty 20 to regain control.
Weapons fire is not possible while the vehicle remains out of control.
CONTROL LOSS / CRASH!
Total up the amount by which you missed the Driving/Piloting roll, and apply below:
1-5 Vehicle slews briefly out of control. Weapons fire at -5 this turn. 6-9 Vehicle slews out of control. All weapons fire at -10 this turn and
next.
10+ Vehicle crashes. No weapons fire from this vehicle. LOCATING VEHICLE DAMAGE
When you attack a vehicle, you will subtract the vehicles armor SP from the damage, then roll 1D10 to determine where the round went if it got through the armor:
VEHICLE DAMAGE
Vehicles have both SP values and Structural Damage Points (SDP). If armored, the vehicle’s SP is subtracted from the damage taken, with the remaining damage subtracted from the vehicle’s SDP. When a vehicle is reduced to 0 SDP, it is considered to be destroyed or inoperable.
VEHICLE HIT LOCATION TABLE D10 Civilian Ground Vehicle Location
1 Tire track (unless otherwise noted tire is 5 SP / 3 SDP Wheel is full SP/SDP)
2-3 Engine (full SP/ x3SDP)
4-6 Driver, crew, or passenger (unless otherwise noted glass is 4 SP / 2 SDP)
7-9 Vehicle body (Full SP/SDP) 10 Cargo
D10 Military Ground Vehicle Location
1 Tire/GE skirt/track (unless otherwise noted tire is 5 SP / 3 SDP Wheel is full SP/SDP)
2-3 Engine (full SP/ x3SDP)
4 Driver or crew (unless otherwise noted glass is 4 SP / 2 SDP) 5 Subsystem.
6-8 Vehicle body (full SP/SDP)
9-10 Turret (body if not present) ( turret is full SP / 1/3 SDP)
D10 Aircraft Location
1-2 Engine (full SP/ x3SDP)
3 Pilot or crew (unless otherwise noted glass is 5 SP / 3 SDP) 4-5 Wings/rotors/fans (unless otherwise noted ½ SP / full SDP)
6 Subsystem.
7-10 Vehicle body (full SP/SDP) DAMAGE EFFECTS
Vehicle Body: When the vehicle has taken its total SDP in damage
(from any combination of locations) the vehicle is rendered inoperable.
Motive Gear: 1/3 total SDP. When the motive systems (tires,
treads, wings) have sustained 1/2 of their SDP, the vehicle's top speed is halved, and it suffers a -3 maneuverability modifier. When the motive systems have lost all their SDP, the vehicle is
immobilized (aerial vehicles crash).
Engine: 1/3 total SDP. If it takes over 1/2 its SDP top speed is
halved, and it suffers a –1 maneuverability modifier. When it has lost all its SDP it is immobilized (aircraft may try to glide). Once the engine has taken over 50% of its SDP in damage, there is a 1 in 10 chance of a fuel explosion - roll this each time the engine takes damage. If the fuel explodes, the vehicle is destroyed.
Pilot or crew: Roll randomly for the crewman hit. Apply the
damage to the person, subtracting personal armor SP from the damage. An unconscious or dead crewmember can't operate the vehicle; most vehicles tend to crash when the driver is
incapacitated.
Subsystem: Roll 1D10:
1 - 3 Weapon ammo: Unless otherwise noted, weapons
have 10 SDP. When a weapon has taken damage to all its SDP, it is destroyed. When a weapon is destroyed, there's a 1 in 10 chance that it will explode, doing the full damage of one shot to the part of the vehicle to which it is attached. If it doesn't explode, the magazine for one random weapon is destroyed.
4 - 6 Cargo: Minor hit destroys 1 item, a Major or
Catastrophic hit destroys all cargo.
7 Communications: Lose all radio or other onboard
comm. systems.
8 ECM/HUD systems: lose all targeting and defensive
jammers.
10 Passengers: (Defender rolls to see who gets it) If more
than one, divide the damage between them as evenly as possible.
Turret: Have 1/3 the vehicle's total SDP. When the turret loses
any SDP, there's a 2 in 10 chance that one of the weapons mounted there will be rendered useless. When the turret takes damage to all its SDP, it and all equipment in it are no longer functional.
VEHICULAR COMBAT FACTORS & CALCULATION (FOR USE AS AN ALTERNATIVE ONLY WHEN DEALING
WITH HEAVY WEAPONS VS. VEHICLES) Maximum Damage/20 for anti-armor explosives, projectiles, and artillery (projectile weapons above 30mm, Anti-Armor rockets, missiles, shaped charge explosives, Railguns, anti- vehicle mines, HEAT, etc...)
Maximum Damage/40 for all anti-personnel weapons (projectile weapons 30mm or below, Anti-personnel rockets, thrown andlaunched grenades, unshaped explosives, anti- personnel mines, etc...)
Multiply x1.5 for standard AP or API
Multiply x2 HEAT, DU, HEDP, HESH, or APFSDS, APDS Multiply x4 for tandem heat
divide by 2 for weapons doing damage in D6 Divide by 2 for hollowpoint or flechette
Divide by 4 for buckshot (including fragmentation weapons) Round up at the end for weapons measured in d10 increments Round down at the end for weapons measured in D6
increments
Armor Value: SP/20, round off. Body Value: SDP/20; round off.
COMBAT PROCEDURE 1. Roll normally for to-hit.
2. Figure Penetration and Armor Modifiers PENETRATION MODIFIERS Per 10 points above target number …. +1/2
Per additional round ... +1/4 Long Range ... -1/4 Extreme Range ... -1/2
ARMOR MODIFIERS
Hitting vehicle from side ... 3/4 Bottom, back, or top ... 1/2 3. Subtract Armor Value from Penetration.
If the result is 0 or more, go to step 4. If not go to step 6. 4. Roll 1D10 and add positive difference between Penetration and Armor Value.
5. Subtract the target's Body Value, and refer to table below: DAMAGE TABLE
Die Roll ... Result 0 or less ... Surface Damage (step 6) 1-5 ... Minor Damage 6-9 ... Major Damage 10+ ... Catastrophic Damage 6. Surface Damage: Roll 1D10. On a 7-10, one random unprotected/exposed piece of equipment has been damaged. If the weapon that damaged it has a base Penetration of 3+, the item is destroyed. If the weapon's Penetration is 2 or less, the item has a 50% chance of surviving in repairable condition. 7. Other Damage: Roll on Vehicle Hit Location Chart to see what was hit, then check below for effects of damage.
HULL/TURRET SUBTABLES Roll 1D10 (+1 if shooting at front, -1 if back)
Roll ... Hull/Turret Location 0-2 ... Cargo or Ammo 3-4 ... Engine/Crew 5-7 ...Crew 8 ... Equipment 9 ... Weapon 10-11 ... Empty Space/Weapon EFFECTS
Cargo: Minor hit destroys 1 item, a Major or Catastrophic hit
destroys all cargo.
Ammo: If it doesn't explode, the magazine for one random weapon
is destroyed.
Engine: A damaged or destroyed engine immobilizes the vehicle.
Empty Space: The shot passes through harmlessly.
MINOR DAMAGE
Equipment, system or weapon: 20% chance that it is destroyed.
If not destroyed, it will not work until repaired.
Fuel: 25% chance of catching on fire (3d6 to each crewmember
and 25% chance of exploding each turn it is on fire). Fire extinguishers and damage-control systems reduce the chance of fire or explosion to 5%.
Crew: Each applicable crewmember sustains 4D6 damage to a
random location. Body armor will reduce damage as normal.
MAJOR DAMAGE
Equipment, system or weapon: 90% chance that it is destroyed.
If not destroyed, it will not work until repaired.
Engine/Explosive Ammo: 50% chance it will explode
demolishing the target. Fire extinguishers and damage-control systems reduce the chance of explosion to 10%.
Fuel: 50% chance of catching on fire (3d6 to each crewmember
and 25% chance of exploding each turn it is on fire). Fire extinguishers and damage-control systems reduce the chance of fire or explosion to 10%.
Crew: Each applicable crewmember sustains 6D6 damage to a
random location. Body armor will reduce damage as normal.
CATASTROPHIC DAMAGE
Equipment, system or weapon: Item destroyed, must be replaced.
Engine/Explosive Ammo: 90% chance it will explode
demolishing the target. Fire extinguishers and damage-control systems reduce the chance of explosion to 30%.
Fuel: 50% chance of catching on fire (3d6 to each crewmember
and 25% chance of exploding each turn it is on fire). Fire extinguishers and damage-control systems reduce the chance of fire or explosion to 30%.
Crew: Each applicable crewmember sustains 10D6 damage to a