Method for judging highway abnormal event

Patent metadata

Field	Value
Publication number	US-10573174-B2
Application number	US-201816318691-A
Country	US
Kind code	B2
Filing date	Mar 28, 2018
Priority date	Jul 4, 2017
Publication date	Feb 25, 2020
Grant date	Feb 25, 2020

Abstract

The present invention provides a method for judging a highway abnormal event, which can determine the traffic jam phenomenon in the target road segment based on the trajectory data of each sample vehicle of the target road segment. The solution of the present invention has the following beneficial effects of 1. comprehensively considering the vehicle speed information of the sample vehicles to judge the traffic jam event; 2. determining the overall traffic jam event of the target road segment; 3. more accurately judging the traffic jam event of the target road segment.

First claim

The invention claimed is:

1. A method for judging a highway abnormal event is provided, including:
step 1: obtaining trajectory data of sample vehicles passing a target road segment H within a target time period T;
step 2: equally dividing the T and the H respectively, and constructing a two-dimensional matrix U representing the discretized trajectorys of the sample vehicles based on the equally divided T and H;
step 3: calculating an average speed of the sample vehicles at spatio-temporal points in the discretized trajectorys, and adding the average speed of the spatio-temporal points to the two-dimensional matrix U;
step 4: calculating a total number of sample vehicles at the spatio-temporal points in the discretized trajectorys and the average speed of all sample vehicles at the spatio-temporal points in the discretized trajectorys; and
step 5: obtaining traffic jam conditions in the T and the H based on the total number of sample vehicles at the spatio-temporal points in the discretized trajectorys and the average speed of all sample vehicles at the spatio-temporal points in the discretized trajectorys.

2. The method according to claim 1 , wherein the step 1 further includes:
selecting a closed polygon A around the target road segment, so that the shortest distance from any point on the A to the target road segment is equal, wherein
the shortest distance is the maximum positioning offset distance of the sample vehicle that can be positioned on the target road segment; and
the trajectorys of the sample vehicles are obtained and are expressed as S=[(t 1 ,l 1 ), (t 2 ,l 2 ), . . . , (t n ,l n )], wherein the ith record R i =(t i ,l i ) expresses that the time is t i , and the location of the sample vehicle is l i .

3. The method according to claim 2 , wherein the step 2 further includes:
dividing the H into m continuous road segments H=H 1 +H 2 + . . . +H m with equal lengths;
dividing the T into n time periods with equal intervals, wherein the intermediate time point of the time segment i is expressed as T i ; and
constructing the two-dimensional matrix U representing the discretized trajectorys of the sample vehicles based on the divided road segments and time periods.

4. The method according to claim 3 , wherein the step of constructing the two-dimensional matrix U representing the discretized trajectorys of the sample vehicles based on the divided road segments and time periods in the step 2 further includes:
finding starting points H a and ending points H b of the trajectories S=[(t 1 ,l 1 ), (t 2 ,l 2 ), . . . , (t n ,l n )] of the sample vehicles, wherein l 1 ∈H a , l n ∈H b , and the H is expressed as H ab ={H a , H a+1 , . . . , H b };
finding starting time points T c and ending time points T d respectively corresponding to the trajectorys t 1 and t n of the sample vehicles, wherein T c−1 <t 1 ≤T d , T c ≤t n <T d+1 , and the time points included in the trajectorys of the sample vehicles are expressed as T cd ={T c , T c+1 , . . . , T d };
finding location information corresponding to the time points T i in the trajectorys of the sample vehicles, wherein t k <T i <t k+1 , wherein the trajectory points corresponding to the t k and t k+1 are P(t k ,l k ),Q(t k+1 ,l k+1 );
obtaining the road segment H i corresponding to the T i based on the l k and the l k+1 ; and
constructing the two-dimensional matrix U representing the discretized trajectorys of the sample vehicles based on the T i and H i , wherein the discretized trajectorys are expressed as S′=[(H 1 ,T 1 ),(H 2 ,T 2 ),(H 2 ,T 3 ),(H 3 ,T 4 ),(H 5 ,T 5 ), . . . ].

5. The method according to claim 4 , wherein the step of obtaining the road segment H i corresponding to the T i based on the l k and the l k+1 in the step 2 further includes:
when the l k and the l k+1 are on the same segment of trajectory H i , indicating that the road segment corresponding to the sample vehicle at the moment T i is H i ;
when the l k and the l k+1 are respectively located on two different road segments Hj and Hj+r, assuming that the sample vehicle performs uniform linear motion between the l k and the l k+1 ;
calculating the speed

v
=



l

k
+
1

-

l
k



t

k
+
1

-

t
k

between the l k and the k k+1 , obtaining that the sample vehicle is located between the l k and the l k+1 at the moment T i , and indicating that the distance from the l k is v·(t k+1 −t k ), that is, the geographical location of the target vehicle is W=l k +v·(t k+1 −t k ); and
finding the road segment where the W is located from the H ab , that is, the road segment H i corresponding to the sample vehicle at the moment T i .

6. The method according to claim 5 , wherein the step of calculating the average speed of the sample vehicles at spatio-temporal points in the discretized trajectorys in the step 3 further includes:
for any discretized trajectory point of the sample vehicle, finding from the original trajectory S=[(t 1 ,l 1 ), (t 2 ,l 2 ), . . . , (t n ,l n )] two trajectory points X and Y before and after the any discretized trajectory point respectively, wherein the X and Y are closest to the any discretized trajectory point and are not located on the same road segment as the any discretized trajectory point; and
expressing the average speed of the sample vehicle at the any discretized trajectory point by using the average speed of the road segment between the X and the Y.

7. The method according to claim 6 , wherein the step of calculating the total number of sample vehicles at the spatio-temporal points in the discretized trajectorys in the step 4 further includes:
merging the trajectory matrixes U of all sample vehicles into a three-dimensional matrix D=[U 1 , U 2 , . . . , U n ], wherein u represents the number of the sample vehicles, D x , D y , D z respectively represent three dimensions of the three-dimensional matrix D, namely, the road segment, the time and the user, any element D(i,j,k) in the matrix represents the number of users at the ith road segment and the jth time point;
expressing the total number of the sample vehicles at the spatio-temporal points in the discretized trajectorys by using a two-dimensional matrix E, wherein E(i,j) represents the number of users at the ith road segment and the jth time point; and
traversing the two dimensions of D x and D y of the three-dimensional matrix D to find a non-empty element set D′ ij ; E(i,j)=|D′ ij | in the D(i,j,:) for all i and j.

8. The method according to claim 7 , wherein the step of calculating the average speed of all sample vehicles at the spatio-temporal points in the discretized trajectorys in the step 4 further includes:
recording the average speed of each road segment in a speed two-dimensional matrix F, wherein F(i,j) represents the average speed of all sample vehicles at the ith road segment and the jth time point:

Assignees

• Shandong Provincial Communications Planning And Design Inst
• Univ Tsinghua

Inventors

• Zhao Kai
• Bi Yufeng
• Li Yong
• Liu Wei
• Jin Depeng
• Wu Weiling
• Zhou Pengfei
• Su Li
• Tu Zhen
• Mu Tao
• Fang Peiyang
• Pang Huajun
• Ma Chuanyi

Classifications

• G08G1/0133 Primary

  for classifying traffic situation · CPC title

• G08G1/0112

  from the vehicle, e.g. floating car data [FCD] · CPC title

• G08G1/052

  with provision for determining speed or overspeed {(speed measuring in general G01P)} · CPC title