Why the @#$% is there so much traffic? - Benjamin Seibold

568,337 views ใƒป 2020-05-28

TED-Ed


ืื ื ืœื—ืฅ ืคืขืžื™ื™ื ืขืœ ื”ื›ืชื•ื‘ื™ื•ืช ื‘ืื ื’ืœื™ืช ืœืžื˜ื” ื›ื“ื™ ืœื”ืคืขื™ืœ ืืช ื”ืกืจื˜ื•ืŸ.

ืชืจื’ื•ื: ืขืจื™ื›ื”: Ido Dekkers
00:06
Youโ€™re cruising down the highway when all of a sudden
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ืืชื ืžืฉื™ื™ื˜ื™ื ืœื›ื ื‘ืžื•ืจื“ ื”ื›ื‘ื™ืฉ ื”ืžื”ื™ืจ ื›ืฉืคืชืื•ื
00:09
endless rows of brake lights appear ahead.
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ืฉื•ืจื•ืช ืื™ืŸ ืกื•ืคื™ื•ืช ืฉืœ ืื•ืจื•ืช ื‘ืœื™ืžื” ืžื•ืคื™ืขื•ืช ืœืคื ื™ื›ื.
00:12
Thereโ€™s no accident, no stoplight,
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ืื™ืŸ ืชืื•ื ื”, ืื™ืŸ ืจืžื–ื•ืจื™ื,
00:14
no change in speed limit or narrowing of the road.
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ืื™ืŸ ืฉื™ื ื•ื™ ื‘ืžื”ื™ืจื•ืช ื”ืžื•ืชืจืช ืื• ื”ืฆืจื” ืฉืœ ื”ื›ื‘ื™ืฉ.
00:17
So why the @#$%! is there so much traffic?
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ืื– ืœืžื” ืœืขื–ืื–ืœ ื™ืฉ ื›ืœ ื›ืš ื”ืจื‘ื” ืชื ื•ืขื”?
ื›ืฉืชื ื•ืขื” ืžื’ื™ืขื” ืœืขืฆื™ืจื” ื›ืžืขื˜ ืžื•ื—ืœื˜ืช ืœืœื ืกื™ื‘ื”,
00:21
When traffic comes to a near standstill for no apparent reason,
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00:24
itโ€™s called a phantom traffic jam.
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ื–ื” ื ืงืจื ืคืงืง ืคืื ื˜ื•ื.
00:27
A phantom traffic jam is an emergent phenomenon
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ืคืงืง ืคืื ื˜ื•ื ื”ื•ื ืชื•ืคืขื” ืขื•ืœื”
00:30
whose behavior takes on a life of its own, greater than the sum of its parts.
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ืฉื”ื”ืชื ื”ื’ื•ืช ืฉืœื” ืžืงื‘ืœืช ื—ื™ื™ื ืžืฉืœ ืขืฆืžื”, ืฉื’ื“ื•ืœื™ื ืžืกื›ื•ื ื—ืœืงื™ื”.
ืื‘ืœ ืœืžืจื•ืช ื›ืœ ื–ืืช, ืื ื—ื ื• ืœืžืขืฉื” ื™ื›ื•ืœื™ื ืœืžื“ืœ ืืช ื”ืคืงืงื™ื ื”ืืœื”,
00:35
But in spite of this, we can actually model these jams,
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00:38
even understand the principles that shape themโ€”
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ืืคื™ืœื• ืœื”ื‘ื™ืŸ ืืช ื”ืขืงืจื•ื ื•ืช ืฉื™ื•ืฆืจื™ื ืื•ืชื --
00:41
and weโ€™re closer than you might think
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ื•ืื ื—ื ื• ืงืจื•ื‘ื™ื ืžืฉืืชื ื—ื•ืฉื‘ื™ื
00:43
to preventing this kind of traffic in the future.
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ื›ื“ื™ ืœืžื ื•ืข ืกื•ื’ ื›ื–ื” ืฉืœ ืชื ื•ืขื”.
00:46
For a phantom traffic jam to form, there must be a lot of cars on the road.
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ื›ื“ื™ ืฉืคืงืง ืคืื ื˜ื•ื ื™ื•ื•ืฆืจ, ื—ื™ื™ื‘ื•ืช ืœื”ื™ื•ืช ื”ืจื‘ื” ืžื›ื•ื ื™ื•ืช ืขืœ ื”ื›ื‘ื™ืฉ.
00:51
That doesnโ€™t mean there are necessarily too many cars
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ื–ื” ืœื ืื•ืžืจ ืฉื™ืฉ ื‘ื”ื›ืจื— ื™ื•ืชืจ ืžื“ื™ ืžื›ื•ื ื™ื•ืช
00:54
to pass through a stretch of roadway smoothly,
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ื›ื“ื™ ืœืขื‘ื•ืจ ื‘ืงื˜ืข ื“ืจืš ื‘ืื•ืคืŸ ื—ืœืง,
00:56
at least not if every driver maintains the same consistent speed and spacing
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ืœืคื—ื•ืช ืœื ืื ื›ืœ ื ื”ื’ ืฉื•ืžืจ ืขืœ ืื•ืชื” ืžื”ื™ืจื•ืช ื•ืจื™ื•ื•ื—
01:01
from other drivers.
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ืžื ื”ื’ื™ื ืื—ืจื™ื.
01:02
In this dense, but flowing, traffic,
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ื‘ืชื ื•ืขื” ื”ื“ื—ื•ืกื” ืื‘ืœ ื–ื•ืจืžืช ื”ื–ื•,
01:04
it only takes a minor disturbance to set off the chain of events
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ื–ื” ื“ื•ืจืฉ ืจืง ื”ืคืจืขื” ืงื˜ื ื” ื›ื“ื™ ืœื”ืฆื™ืช ืฉืจืฉืจืช ืฉืœ ืืจื•ืขื™ื
01:09
that causes a traffic jam.
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ืฉื’ื•ืจืžื™ื ืคืงืง ืชื ื•ืขื”.
01:11
Say one driver brakes slightly.
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ื ื’ื™ื“ ืฉื ื”ื’ ืื—ื“ ื‘ื•ืœื ืงืฆืช.
01:14
Each successive driver then brakes a little more strongly,
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ื›ืœ ื ื”ื’ ืื—ืจื™ื• ื‘ื•ืœื ืื– ืžืขื˜ ื—ื–ืง ื™ื•ืชืจ,
01:18
creating a wave of brake lights that propagates backward
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ื•ื™ื•ืฆืจ ื’ืœ ืฉืœ ืื•ืจื•ืช ื‘ืœื™ืžื” ืฉืžื—ืœื—ืœื™ื ืื—ื•ืจื”
01:21
through the cars on the road.
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ื“ืจืš ื”ืžื›ื•ื ื™ื•ืช ืขืœ ื”ื›ื‘ื™ืฉ.
01:23
These stop-and-go waves can travel along a highway for miles.
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ื’ืœื™ ื”ืขืฆื™ืจื” ื•ื ืกื™ืขื” ื”ืืœื” ื™ื›ื•ืœื™ื ืœื ื•ืข ืœืื•ืจืš ื”ื›ื‘ื™ืฉ ื”ืžื”ื™ืจ ืœืื•ืจืš ืงื™ืœื•ืžื˜ืจื™ื.
01:28
With a low density of cars on the road,
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ืขื ืฆืคื™ืคื•ืช ื ืžื•ื›ื” ืฉืœ ืžื›ื•ื ื™ื•ืช ืขืœ ื”ื›ื‘ื™ืฉ,
01:31
traffic flows smoothly because small disturbances,
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ื”ืชื ื•ืขื” ื–ื•ืจืžืช ื‘ืื•ืคืŸ ื—ืœืง ื‘ื’ืœืœ ืฉื”ืคืจืขื•ืช ืงื˜ื ื•ืช,
01:34
like individual cars changing lanes or slowing down at a curve,
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ื›ืžื• ืžื›ื•ื ื™ื•ืช ื‘ื•ื“ื“ื•ืช ืฉืžืฉื ื•ืช ื ืชื™ื‘ ืื• ืžืื™ื˜ื•ืช ื‘ืกื™ื‘ื•ื‘,
01:38
are absorbed by other driversโ€™ adjustments.
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ื ืกืคื’ื•ืช ืขืœ ื™ื“ื™ ื”ืชืืžื•ืช ืฉืœ ื ื”ื’ื™ื ืื—ืจื™ื.
01:41
But once the number of cars on the road exceeds a critical density,
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ืื‘ืœ ื‘ืจื’ืข ืฉืžืกืคืจ ื”ืžื›ื•ื ื™ื•ืช ืขืœ ื”ื›ื‘ื™ืฉ ืขื•ืœื” ืขืœ ื”ื“ื—ื™ืกื•ืช ื”ืงืจื™ื˜ื™ืช,
01:45
generally when cars are spaced less than 35 meters apart,
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ื‘ื“ืจืš ื›ืœืœ ื›ืฉืžื›ื•ื ื™ื•ืช ืžืจื•ื•ื—ื•ืช ื‘ืžืจื—ืง ืฉืœ ืคื—ื•ืช ืž 35 ืžื˜ืจ,
01:50
the systemโ€™s behavior changes dramatically.
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ื”ืชื ื”ื’ื•ืช ื”ืžืขืจื›ืช ืžืฉืชื ื” ื“ืจืžื˜ื™ืช.
01:53
It begins to display dynamic instability, meaning small disturbances are amplified.
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ื”ื™ื ืžืชื—ื™ืœื” ืœื”ืฆื™ื’ ื—ื•ืกืจ ื™ืฆื™ื‘ื•ืช ื“ื™ื ืžื™ืช, ืžื” ืฉืื•ืžืจ ืฉื”ืคืจืขื•ืช ืงื˜ื ื•ืช ืžื•ื’ื‘ืจื•ืช.
01:59
Dynamic instability isnโ€™t unique to phantom traffic jamsโ€”
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ื—ื•ืกืจ ื™ืฆื™ื‘ื•ืช ื“ื™ื ืžื™ ืœื ื™ื—ื•ื“ื™ ืœืคืงืงื™ ืคืื ื˜ื•ื --
02:03
itโ€™s also responsible for raindrops, sand dunes, cloud patterns, and more.
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ื”ื•ื ื’ื ืื—ืจืื™ ืœื˜ื™ืคื•ืช ื’ืฉื, ื“ื™ื•ื ื•ืช ื—ื•ืœ, ืฆื•ืจื•ืช ืขื ื ื™ื, ื•ืขื•ื“.
02:10
The instability is a positive feedback loop.
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ื—ื•ืกืจ ื”ื™ืฆื™ื‘ื•ืช ื”ื™ื ืœื•ืœืืช ืžืฉื•ื‘ ื—ื™ื•ื‘ื™ืช.
02:13
Above the critical density,
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ืžืขืœ ื“ื—ื™ืกื•ืช ืงืจื™ื˜ื™ืช,
ื›ืœ ืจื›ื‘ ื ื•ืกืฃ ืžืคื—ื™ืช ืืช ืžืกืคืจ ื”ืžื›ื•ื ื™ื•ืช ื‘ืฉื ื™ื”
02:15
any additional vehicle reduces the number of cars per second
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02:19
passing through a given point on the road.
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ืฉืขื•ื‘ืจื•ืช ื“ืจืš ื ืงื•ื“ื” ื ืชื•ื ื” ื‘ื›ื‘ื™ืฉ.
02:22
This in turn means it takes longer for a local pileup
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ื–ื” ื‘ืชืžื•ืจื” ืื•ืžืจ ืฉืœื•ืงื— ื–ืžืŸ ืจื‘ ื™ื•ืชืจ ืœืคืงืง ืžืงื•ืžื™
02:26
to move out of a section of the road, increasing vehicle density even more,
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ืœื ื•ืข ืžื—ื•ืฅ ืœืงื˜ืข ืžืกื•ื™ื™ื ื‘ื›ื‘ื™ืฉ, ืžื” ืฉืžื’ื‘ื™ืจ ืืช ื”ื“ื—ื™ืกื•ืช ืืคื™ืœื• ื™ื•ืชืจ,
02:31
which eventually adds up to stop-and-go traffic.
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ืžื” ืฉืœื‘ืกื•ืฃ ืžืชื•ื•ืกืฃ ืœืชื ื•ืขื” ืฉืขื•ืฆืจืช ื•ื ื•ืกืขืช.
02:35
Drivers tend not to realize they need to break far in advance of a traffic jam,
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ื ื”ื’ื™ื ื ื•ื˜ื™ื ืœื ืœื”ื‘ื™ืŸ ืฉื”ื ืฆืจื™ื›ื™ื ืœื‘ืœื•ื ื”ืจื‘ื” ืœืคื ื™ ื”ืคืงืง,
02:40
which means they end up having to brake harder to avoid a collision.
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ืžื” ืฉืื•ืžืจ ืฉื”ื ืฆืจื™ื›ื™ื ืœื‘ืœื•ื ื—ื–ืง ื™ื•ืชืจ ื›ื“ื™ ืœืžื ื•ืข ื”ืชื ื’ืฉื•ืช.
02:44
This strengthens the wave of braking from vehicle to vehicle.
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ื–ื” ืžื—ื–ืง ืืช ื’ืœ ื”ื‘ืœื™ืžื•ืช ืžืจื›ื‘ ืœืจื›ื‘.
02:48
Whatโ€™s more, drivers tend to accelerate too rapidly out of a slowdown,
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ื‘ื ื•ืกืฃ, ื ื”ื’ื™ื ื ื•ื˜ื™ื ืœื”ืื™ืฅ ืžื”ืจ ืžื“ื™ ืื—ืจื™ ื”ื”ืื˜ื”,
02:53
meaning they try to drive faster
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ืžื” ืฉืื•ืžืจ ืฉื”ื ืžื ืกื™ื ืœื ื”ื•ื’ ืžื”ืจ ื™ื•ืชืจ
02:55
than the average flow of traffic downstream of them.
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ืžื”ื–ืจื™ืžื” ื”ืžืžื•ืฆืขืช ืฉืœ ื”ืชื ื•ืขื” ื‘ื”ืžืฉืš.
02:58
Then, they have to brake again, eventually producing another feedback loop
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ืื–, ื”ื ื—ื™ื™ื‘ื™ื ืœื‘ืœื•ื ืฉื•ื‘, ื•ืœื‘ืกื•ืฃ ืžื™ื™ืฆืจื™ื ืœื•ืœืืช ืžืฉื•ื‘ ื ื•ืกืคืช
03:02
that causes more stop-and-go traffic.
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ืฉื’ื•ืจืžืช ืขื•ื“ ืชื ื•ืขืช ืขืฆื™ืจื” ื•ื ืกื™ืขื”.
03:05
In both cases, drivers make traffic worse
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ื‘ืฉื ื™ ื”ืžืงืจื™ื, ื ื”ื’ื™ื ืžืจืขื™ื ืืช ื”ืชื ื•ืขื”
03:09
simply because they donโ€™t have a good sense of the conditions ahead of them.
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ืคืฉื•ื˜ ื‘ื’ืœืœ ืฉืื™ืŸ ืœื”ื ื—ื•ืฉ ื˜ื•ื‘ ืœืžืฆื‘ ืฉืœืคื ื™ื”ื.
03:13
Self driving cars equipped with data on traffic conditions ahead
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ืžื›ื•ื ื™ื•ืช ืื•ื˜ื•ื ื•ืžื™ื•ืช ืฉืžืฆื•ื™ื™ื“ื•ืช ื‘ืžื™ื“ืข ืขืœ ืžืฆื‘ ื”ืชื ื•ืขื” ืœืคื ื™ื”ืŸ
ืžืจื›ื‘ื™ื ืžื—ื•ื‘ืจื™ื ืื• ื—ื™ื™ืฉื ื™ื ื‘ื›ื‘ื™ืฉ
03:18
from connected vehicles or roadway sensors
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03:21
might be able to counteract phantom traffic in real-time.
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ืื•ืœื™ ื™ื•ื›ืœื• ืœื”ืชื’ื‘ืจ ืขืœ ืคืงืงื™ ืคืื ื˜ื•ื ื‘ื–ืžืŸ ืืžืช.
03:24
These vehicles would maintain a uniform speed, safety permitting,
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ื”ืจื›ื‘ื™ื ื”ืืœื” ื™ืฉืžืจื• ืขืœ ืžื”ื™ืจื•ืช ืื—ื™ื“ื”, ืื ื”ื‘ื˜ื™ื—ื•ืช ืžืืคืฉืจืช,
03:29
that matches the average speed of the overall flow,
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ืฉืžืชืื™ืžื” ืืช ื”ืžื”ื™ืจื•ืช ื”ืžืžื•ืฆืขืช ืฉืœ ื”ืชื ื•ืขื” ื‘ื›ืœืœื•ืชื”,
03:32
preventing traffic waves from forming.
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ืžื” ืฉื™ืžื ืข ื’ืœื™ื ื‘ืชื ื•ืขื” ืžืœื”ื•ื•ืฆืจ.
03:35
In situations where thereโ€™s already a traffic wave,
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ื‘ืžืฆื‘ื™ื ื‘ื”ื ื›ื‘ืจ ื™ืฉ ื’ืœื™ื ื‘ืชื ื•ืขื”,
03:38
the automated vehicle would be able to anticipate it,
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ื”ืจื›ื‘ื™ื ื”ืื•ื˜ื•ื ื•ืžื™ื ื™ื”ื™ื• ืžืกื•ื’ืœื™ื ืœืฆืคื•ืช ืืช ื–ื”,
03:41
braking sooner and more gradually than a human driver
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ืœื‘ืœื•ื ืžื•ืงื“ื ื™ื•ืชืจ ื•ื‘ื”ื“ืจื’ื” ืžืืฉืจ ื ื”ื’ื™ื ืื ื•ืฉื™ื™ื
03:44
and reducing the strength of the wave.
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ื•ืœื”ืคื—ื™ืช ืืช ื›ื•ื— ื”ื’ืœื™ื.
03:47
And it wouldnโ€™t take that many self-driving carsโ€”
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ื•ื–ื” ืœื ื™ื“ืจื•ืฉ ื”ืจื‘ื” ืžื›ื•ื ื™ื•ืช ืื•ื˜ื•ื ื•ืžื™ื•ืช --
03:51
In a recent experiment, one autonomous vehicle for every 20 human drivers
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ื‘ื ื™ืกื•ื™ ืฉื ืขืจืš ืœืื—ืจื•ื ื”, ืจื›ื‘ ืื•ื˜ื•ื ื•ืžื™ ืื—ื“ ืขืœ ื›ืœ 20 ืžื›ื•ื ื™ื•ืช ืขื ื ื”ื’ื™ื ืื ื•ืฉื™ื™ื
03:56
was enough to dampen and prevent traffic waves.
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ื”ื™ื” ืžืกืคื™ืง ื›ื“ื™ ืœืฉื›ืš ื•ืœืžื ื•ืข ื’ืœื™ ืชื ื•ืขื”.
04:00
Traffic jams are not only a daily annoyanceโ€“
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ืคืงืงื™ ืชื ื•ืขื” ื”ื ืœื ืจืง ืžืคื’ืข ื™ื•ื ื™ื•ืžื™ --
04:03
theyโ€™re a major cause of fatalities,
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ื”ื ื’ื ื’ื•ืจื ืขื™ืงืจื™ ืœืงื•ืจื‘ื ื•ืช,
04:05
wasted resources, and planet-threatening pollution.
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ืžืฉืื‘ื™ื ืžื‘ื•ื–ื‘ื–ื™ื, ื•ื–ื™ื”ื•ื ื—ื•ื‘ืง ืขื•ืœื.
04:09
But new technology may help reduce these patterns,
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ืื‘ืœ ื˜ื›ื ื•ืœื•ื’ื™ื•ืช ื—ื“ืฉื•ืช ืื•ืœื™ ื™ืขื–ืจื• ืœื”ืคื—ื™ืช ืืช ื”ืชื‘ื ื™ื•ืช ื”ืืœื•,
04:12
rendering our roads safer,
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ืžื” ืฉื™ื”ืคื•ืš ืืช ื”ื›ื‘ื™ืฉื™ื ืœื‘ื˜ื•ื—ื™ื ื™ื•ืชืจ,
04:14
our daily commutes more efficient, and our air cleaner.
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ื”ื ืกื™ืขื•ืช ื”ื™ื•ื ื™ื•ืžื™ื•ืช ืœื™ื•ืชืจ ื™ืขื™ืœื•ืช, ื•ื”ืื•ื™ืจ ืฉืœื ื• ืœื ืงื™ ื™ื•ืชืจ.
ื•ื‘ืคืขื ื”ื‘ืื” ืฉืืชื ืชืงื•ืขื™ื ื‘ืชื ื•ืขื”,
04:18
And the next time youโ€™re stuck in traffic,
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04:20
it may help to remember that other drivers arenโ€™t necessarily driving spitefully,
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ืื•ืœื™ ื™ืขื–ื•ืจ ืœื–ื›ื•ืจ ืฉื ื”ื’ื™ื ืื—ืจื™ื ืœื ื‘ื”ื›ืจื— ื ื•ื”ื’ื™ื ื›ื“ื™ ืœื”ืจื’ื™ื–,
04:24
but are simply unaware of road conditions aheadโ€” and drive accordingly.
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ืืœื ืคืฉื•ื˜ ืœื ืžื•ื“ืขื™ื ืœืชื ืื™ ื”ื“ืจืš ืœืคื ื™ื”ื -- ื•ื ื•ื”ื’ื™ื ื‘ื”ืชืื.
ืขืœ ืืชืจ ื–ื”

ืืชืจ ื–ื” ื™ืฆื™ื’ ื‘ืคื ื™ื›ื ืกืจื˜ื•ื ื™ YouTube ื”ืžื•ืขื™ืœื™ื ืœืœื™ืžื•ื“ ืื ื’ืœื™ืช. ืชื•ื›ืœื• ืœืจืื•ืช ืฉื™ืขื•ืจื™ ืื ื’ืœื™ืช ื”ืžื•ืขื‘ืจื™ื ืขืœ ื™ื“ื™ ืžื•ืจื™ื ืžื”ืฉื•ืจื” ื”ืจืืฉื•ื ื” ืžืจื—ื‘ื™ ื”ืขื•ืœื. ืœื—ืฅ ืคืขืžื™ื™ื ืขืœ ื”ื›ืชื•ื‘ื™ื•ืช ื‘ืื ื’ืœื™ืช ื”ืžื•ืฆื’ื•ืช ื‘ื›ืœ ื“ืฃ ื•ื™ื“ืื• ื›ื“ื™ ืœื”ืคืขื™ืœ ืืช ื”ืกืจื˜ื•ืŸ ืžืฉื. ื”ื›ืชื•ื‘ื™ื•ืช ื’ื•ืœืœื•ืช ื‘ืกื ื›ืจื•ืŸ ืขื ื”ืคืขืœืช ื”ื•ื•ื™ื“ืื•. ืื ื™ืฉ ืœืš ื”ืขืจื•ืช ืื• ื‘ืงืฉื•ืช, ืื ื ืฆื•ืจ ืื™ืชื ื• ืงืฉืจ ื‘ืืžืฆืขื•ืช ื˜ื•ืคืก ื™ืฆื™ืจืช ืงืฉืจ ื–ื”.

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