CN102254430A - Method for distinguishing accident-prone road section by using traffic conflicts - Google Patents

Abstract

The invention discloses a method for distinguishing an accident-prone road section by using traffic conflicts, which relates to a method for determining the accident-prone road section by using the conflicts among vehicles in a road section so as to quickly and accurately determine the accident-prone road section in a short period and provide reference for the reason analysis of the accident-prone road section and corresponding improving measure providing. The method comprises the following steps of: dividing the road section to determine the traffic conflict occurrence rule of the road section; introducing the quantile of traffic conflict probability distribution, and selecting a traffic conflict times corresponding to the quantile as a critical traffic conflict times to serve as a standard for judging whether the road section is the accident-prone road section; calculating the critical traffic conflict times; measuring and calculating a road section traffic conflict times C by using video processing software, namely a Vehicle Video-Capture Data Collector; and comparing the road section traffic conflict times C with the critical traffic conflict times to judge whether the road section is the accident-prone road section.

Description

A kind of method of utilizing traffic conflict differentiation accident easily to send out the highway section

Technical field

The present invention relates to utilize the conflict differentiation accident between the vehicle of highway section easily to send out the highway section, with reach in a short time fast, accurately judgement accident easily sends out the highway section, easily send out the genetic analysis in highway section and propose corresponding improvement measure foundation is provided for carrying out accident.Belong to the control of traffic and road field.

Background technology

Traffic conflict is meant that under observable condition two or more road users are approaching mutually on time and space, to such an extent as to if either party does not change its movement locus, just will bump.The essence of traffic conflict is the form of expression of traffic behavior unsafe factor, its development both may cause accident to take place, also may avoid accident to take place because of the hedging behavior of taking is proper, thereby accident exists very similar forms with conflicting, and both unique difference are whether direct injurious consequences has taken place.Show according to investigation both domestic and external: accident with conflict between exist certain fallback relationship, especially serious conflict has good linear relationship with traffic hazard.

Through inventor's discovery that studies for a long period of time, collect a long time cycle of traffic hazard data needs of satisfying the sample size requirement, cause identification effect low.Secondly, have the characteristics in " big zone " based on the method for discrimination of statistics of traffic accidents, the incompatible accident of differentiating the zonule is easily sent out the differentiation requirement in highway section.If can seek a kind of mode, can either obtain a large amount of statistical number fast, can embody accidents hazardous characteristic again, the accident that then can significantly improve is easily sent out efficient and the confidence level that the highway section is differentiated.

Summary of the invention

Technical matters: the purpose of this invention is to provide a kind of method of utilizing traffic conflict differentiation accident easily to send out the highway section, when satisfying accident and easily sending out highway section discrimination precision demand, the shortening accident is easily sent out the highway section sense cycle, provides foundation for the road safety measure improves.

Technical scheme: for achieving the above object, the present invention adopts following technical scheme:

A kind of method of utilizing traffic conflict differentiation accident easily to send out the highway section, the concrete steps of described method are:

Step 1) will be to be judged road-section average be divided into n little highway section, n be the natural number more than or equal to 50, and makes the length in each little highway section less than 1m, the number of times of the traffic conflict of path section generation is less than twice, that is: in 5～10 seconds

So, wait to judge that the highway section at the traffic conflict number of times X that 5-10 took place in second is:

X＝X ₁+X ₂+……＝∑X _i，

And, wait to judge that the traffic conflict probability that the highway section took place is in 5～10 seconds:

$P\left(X\right|\mathrm{\λ})=\frac{{\mathrm{\λ}}^X\·e^{-\mathrm{\λ}}}{X!}---\left(1\right)$

Wherein, λ is being for waiting to judge the highway section and in the observation period, the mean value of the traffic conflict observed reading of each hour,

Step 2) the α quantile of introducing traffic conflict probability distribution, selecting the traffic conflict number of times of α quantile correspondence is critical traffic conflict number of times τ, easily sends out the factor in highway section as the accident that takes a decision as to whether, and satisfies following formula:

${\∫}_{-\∞}^{\mathrm{\τ}}P\left(X\right|\mathrm{\λ})\mathrm{dX}=1-\mathrm{\α}---\left(2\right)$

And selecting the pairing traffic conflict number of times of 0.1 quantile of traffic conflict probability distribution is critical traffic conflict number of times, calculates critical traffic conflict number of times τ,

When λ≤20,, formula (2) tries to achieve the τ value by being carried out iterative computation;

When λ＞20,

$\mathrm{\τ}\≈\mathrm{\λ}+{\mathrm{\μ}}_{\mathrm{\α}/2}\sqrt{\mathrm{\λ}}---\left(3\right)$

Wherein, μ _α/2Be the standardized normal distribution fractile,

Step 3) is calculated highway section traffic conflict number of times factory

With traffic conflict classification conflict angle θ ₁Traffic conflict during ∈ (0,30 °) is conflict in the same way,

With traffic conflict classification conflict angle θ ₂Traffic conflict during ∈ (30 °, 90 °) is the side direction conflict,

To satisfy conflict vehicle relative velocity v 〉=10m/s and conflict angle θ ₃∈ (90 °, 180 °) condition be the subtend conflict and,

With spacing D before and after satisfying on the same track _h≤ 5m and back vehicle speed conflict for knocking into the back with front truck speed difference DELTA v＞5m/s condition;

Use Vehicle Video-Capture Data Collector Video processing software, conflicted in the same way, the number of times of side direction conflict, subtend conflict and the conflict of knocking into the back, accumulative total is tried to achieve road section traffic volume conflict number of times C,

If the traffic conflict number of times factory in step 4) highway section is greater than critical traffic conflict number of times τ, then this highway section is that an accident is easily sent out the highway section.

Beneficial effect: the present invention compared with prior art has the following advantages:

1. utilize traffic conflict differentiation accident easily to send out the highway section, by introducing the critical traffic conflict number of times of traffic conflict probability distribution quantile and quantile correspondence, the observation traffic conflict number of times in highway section more to be determined and the size of critical traffic conflict number of times, whether differentiate is that accident is easily sent out the highway section, satisfy the accident of differentiating the zonule and easily send out the differentiation requirement in highway section, help shortening the time cycle of differentiation, improve efficient and the precision differentiated, and then accident is easily sent out the highway section carry out genetic analysis, propose corresponding measures to rectify and reform fast, reduce the generation of traffic hazard.

2. the observation and the disposal route of road section traffic volume conflict, increasingly automated, be not subjected to artificial factor, be convenient to obtain objectively, apace the mass data sample, for probability statistical analysis provides reliable basic data, help improving the fiduciary level that the accident-prone road section is differentiated.

3. integrated use distance, conflict angle, velocity contrast, a plurality of parameters of time make defining of traffic conflict more definite and reliable.

Description of drawings:

Fig. 1 accident is easily sent out the highway section and is differentiated process flow diagram.

Embodiment

A kind of method of utilizing traffic conflict differentiation accident easily to send out the highway section, the concrete steps of described method are:

Step 1) will be to be judged road-section average be divided into n little highway section, n be the natural number more than or equal to 50, and makes the length in each little highway section less than 1m, the number of times of the traffic conflict of path section generation is less than twice, that is: in 5～10 seconds

So, wait to judge that the traffic conflict number of times X that the highway section took place is in 5～10 seconds:

X＝X ₁+X ₂+……＝∑X _i，

And, wait to judge that the traffic conflict probability that the highway section took place is in 5～10 seconds:

$P\left(X\right|\mathrm{\λ})=\frac{{\mathrm{\λ}}^X\·e^{-\mathrm{\λ}}}{X!}---\left(1\right)$

Wherein, λ is being for waiting to judge the highway section and in the observation period, the mean value of the traffic conflict observed reading of each hour,

Step 2) the α quantile of introducing traffic conflict probability distribution, selecting the traffic conflict number of times of α quantile correspondence is critical traffic conflict number of times τ, easily sends out the factor in highway section as the accident that takes a decision as to whether, and satisfies following formula:

${\∫}_{-\∞}^{\mathrm{\τ}}P\left(X\right|\mathrm{\λ})\mathrm{dX}=1-\mathrm{\α}---\left(2\right)$

And selecting the pairing traffic conflict number of times of 0.1 quantile of traffic conflict probability distribution is critical traffic conflict number of times, calculates critical traffic conflict number of times τ,

When λ≤20,, formula (2) tries to achieve the τ value by being carried out iterative computation;

When λ＞20,

$\mathrm{\τ}\≈\mathrm{\λ}+{\mathrm{\μ}}_{\mathrm{\α}/2}\sqrt{\mathrm{\λ}}---\left(3\right)$

Wherein, μ _α/2Be the standardized normal distribution fractile,

Step 3) is calculated highway section traffic conflict number of times C

With traffic conflict classification conflict angle θ ₁Traffic conflict during ∈ (0,30 °) is conflict in the same way,

With traffic conflict classification conflict angle θ ₂Traffic conflict during ∈ (30 °, 90 °) is the side direction conflict,

To satisfy conflict vehicle relative velocity v 〉=10m/s and conflict angle θ ₃∈ (90 °, 180 °) condition be the subtend conflict and,

With spacing D before and after satisfying on the same track _h≤ 5m and back vehicle speed conflict for knocking into the back with front truck speed difference DELTA v＞5m/s condition;

Use Vehicle Video-Capture Data Collector Video processing software, conflicted in the same way, the number of times of side direction conflict, subtend conflict and the conflict of knocking into the back, accumulative total is tried to achieve road section traffic volume conflict number of times C,

If the traffic conflict number of times C in step 4) highway section is greater than critical traffic conflict number of times τ, then this highway section is that an accident is easily sent out the highway section.

Below in conjunction with the traffic conflict enquiry data, the present invention will be further described:

1.) divide the highway section

Needs are judged whether to be divided into n little highway section for accident prone road-section average, make the length in each little highway section less than 1m, the number of times of the traffic conflict that the path section takes place in 5～10 seconds is less than twice, then the number of times X of each path section generation traffic conflict in 5～10 seconds _iSatisfy:

So the traffic conflict number of times X that this highway section took place in 5～10 seconds is: X=X ₁+ X ₂+ ...=∑ X _i,

Because X ₁, X ₂, X ₃Between separate, and all obey (0,1) and distribute, then the number of times X obedience binomial distribution of traffic conflict took place in this highway section in 5～10 seconds, promptly X～B (n, p); Because in Probability p≤0.1 that traffic conflict together takes place a certain path section of road, so when sample n 〉=50, by Poisson's law as can be known, X is approximate to submit to Poisson distribution, satisfies following formula:

$P\left(X\right|\mathrm{\λ})=\frac{{\mathrm{\λ}}^X\·e^{-\mathrm{\λ}}}{X!}---\left(1\right)$

Wherein, λ=np is an expection traffic conflict number of times, represents the number of times of the traffic conflict that this highway section took place in 1 hour in theory, estimates according to maximum likelihood, is similar to and thinks

Mean value for the traffic conflict observed reading of each hour in the observation period.

2.) the α quantile of introducing traffic conflict probability distribution

Introduce the α quantile of traffic conflict probability distribution, selecting the traffic conflict number of times τ of α quantile correspondence is critical traffic conflict number of times, easily sends out the standard in highway section as the accident that takes a decision as to whether, and satisfies following formula:

${\∫}_{-\∞}^{\mathrm{\τ}}P\left(X\right|\mathrm{\λ})\mathrm{dX}=1-\mathrm{\α}---\left(2\right)$

According to the requirement of Engineering Reliability, selecting the pairing traffic conflict number of times of 0.1 quantile of traffic conflict probability distribution is critical traffic conflict number of times.

3.) calculate critical traffic conflict number of times τ

As the traffic conflict number of times C in highway section during greater than critical traffic conflict number of times τ, the highway section just can think that an accident easily sends out the highway section, meets Poisson distribution according to road section traffic volume conflict pests occurrence rule, satisfies following formula:

$P\{C>\mathrm{\&tau;}|\mathrm{\&lambda;}\}=\underset{\mathrm{\&tau;}}{\overset{\&infin;}{\mathrm{\&Sigma;}}}\frac{{\mathrm{\&lambda;}}^C{e}^{-\mathrm{\&lambda;}}}{C!}<\mathrm{\&alpha;}---\left(3\right)$

Therefore, the τ value can be tried to achieve by formula (2) is carried out iterative computation; Yet when expection traffic conflict number of times λ＞20, it is very complicated that the utilization probability equation carries out computation process, uses following method to calculate the τ value:

Because the traffic conflict ubiquity on the highway section, and conflict number of times X＞5 according to central limit theorem, have stochastic variable Z:

$Z=\frac{X-\mathrm{np}}{\sqrt{\mathrm{np}(1-\mathrm{np})}}\&ap;\frac{X-\mathrm{\&lambda;}}{\sqrt{\mathrm{\&lambda;}}}---\left(4\right)$

The approximate standardized normal distribution of obeying of stochastic variable Z, can come the critical traffic conflict number of times of approximate solution τ with following formula:

$\mathrm{\&tau;}\&ap;\mathrm{\&lambda;}+{\mathrm{\&mu;}}_{\mathrm{\&alpha;}/2}\sqrt{\mathrm{\&lambda;}}---\left(5\right)$

Wherein, μ _α/2It is the standardized normal distribution fractile.

4.) the detection of road section traffic volume conflict number of times C

Road section traffic volume conflict observation process is finished by video camera, and differentiate the process of traffic conflict and finish automatically by Vehicle Video-Capture Data Collector Video processing software, be the decision criteria of traffic conflict below:

The highway section conflict comprises conflict, side direction conflict, subtend conflict, the conflict of knocking into the back in the same way, and the decision criteria of various traffic conflicts is as follows, and the number of times that every kind of traffic conflict of accumulative total takes place obtains road section traffic volume conflict number of times C.

Conflict utilizes conflict angle θ in the same way ₁As judging parameter, according to traffic conflict classification conflict angle θ ₁Traffic conflict during ∈ (0,30 °) is called conflict in the same way,

Side direction conflict utilization conflict angle θ ₂As judging parameter, according to traffic conflict classification conflict angle θ ₂Traffic conflict during ∈ (30 °, 90 °) is called the side direction conflict,

The subtend conflict utilizes vehicle relative velocity v, conflict angle θ ₃As critical parameter, according to the requirement of meeting sighting distance, the minimum command range l between Facing Movement two cars is 10m, according to traffic psychology research, time of driver's reaction t ₀Be 1s, can calculate conflict vehicle relative velocity v=10m/s by formula v=l/t; The subtend conflict shows as the conflict vehicle and approaches mutually with opposite direction, be headstock with headstock between the collision that conflicts, so the angle θ that conflicts ₃∈ (90 °, 180 °), so, as v 〉=10m/s, θ ₃During ∈ (90 °, 180 °), a subtend conflict takes place,

Spacing D before and after the conflict of knocking into the back is judged on the same track of use _h, back vehicle speed and front truck speed difference DELTA v be as critical parameter, according to the stopping sight distance requirement, front and back car minimum safe distance is 5m; According to traffic psychology research, time of driver's reaction t ₀Be 1s, by Δ v=D _h/ t ₀The critical value that can calculate back vehicle speed and front truck speed difference DELTA v is 5m/s, so, work as D _hWhen≤5m, Δ v＞5m/s, conflict takes place once to knock into the back,

5.) accident is easily sent out the differentiation in highway section

As the road section traffic volume conflict number of times C that detects during, think that so this highway section is that an accident is easily sent out the highway section, satisfies following formula greater than critical traffic conflict number of times τ.

C＞τ (6)

Example: select place, peaceful six highway Ge Tang passenger stations by north direction southward, being positioned at overline bridge is research object of the present invention to the highway section of extending 50m north.Continuous 7 hours highway section conflict observation is carried out in this highway section.Employing is based on the automatic testing method of the road section traffic volume of video technique conflict, finishing analysis the quantity of road section traffic volume conflict.As shown in the table:

Peaceful six road Ge Tang passenger station road section traffic volume conflict statisticses of table 1

Estimate that according to maximum likelihood the mean value of approximate traffic conflict observation data with each hour is as expection conflict value, i.e. λ=73.Under the situation of 0.1 quantile of selecting the traffic conflict probability distribution, μ _α/2=μ _0.05=1.645, according to (5) formula, obtain critical conflict value τ=87, think that the critical value of highway section conflict in this highway section is 87 times/hour.In 7 hours conflict observation, there is one hour conflict number of times to surpass critical value.According to method of discrimination, think that this highway section is that the highway section is easily sent out in conflict, need do further improvement aspect the car speed management and control of highway section, promptly during morning peak, should strengthen Vehicle Speed control, prevent the generation of traffic hazard.

Claims (1)

1. method of utilizing traffic conflict differentiation accident easily to send out the highway section is characterized in that the concrete steps of described method are:

Step 1) will be to be judged road-section average be divided into n little highway section, n be the natural number more than or equal to 50, and makes the length in each little highway section less than 1m, the number of times of the traffic conflict of path section generation is less than twice, that is: in 5～10 seconds

So, wait to judge that the traffic conflict number of times X that the highway section took place is in 5～10 seconds:

X＝X ₁+X ₂+……＝∑X _i，

And, wait to judge that the traffic conflict probability that the highway section took place is in 5～10 seconds:

$P\left(X\right|\mathrm{\&lambda;})=\frac{{\mathrm{\&lambda;}}^X\&CenterDot;e^{-\mathrm{\&lambda;}}}{X!}---\left(1\right)$

Wherein, λ is being for waiting to judge the highway section and in the observation period, the mean value of the traffic conflict observed reading of each hour,

Step 2) the α quantile of introducing traffic conflict probability distribution, selecting the traffic conflict number of times of α quantile correspondence is critical traffic conflict number of times τ, easily sends out the factor in highway section as the accident that takes a decision as to whether, and satisfies following formula:

${\&Integral;}_{-\&infin;}^{\mathrm{\&tau;}}P\left(X\right|\mathrm{\&lambda;})\mathrm{dX}=1-\mathrm{\&alpha;}---\left(2\right)$

And selecting the pairing traffic conflict number of times of 0.1 quantile of traffic conflict probability distribution is critical traffic conflict number of times, calculates critical traffic conflict number of times τ,

When λ≤20,, formula (2) tries to achieve the τ value by being carried out iterative computation;

When λ＞20,

$\mathrm{\&tau;}\&ap;\mathrm{\&lambda;}+{\mathrm{\&mu;}}_{\mathrm{\&alpha;}/2}\sqrt{\mathrm{\&lambda;}}---\left(3\right)$

Wherein, μ _α/2Be the standardized normal distribution fractile,

Step 3) is calculated highway section traffic conflict number of times C

With traffic conflict classification conflict angle θ ₁Traffic conflict during ∈ (0,30 °) is conflict in the same way,

With traffic conflict classification conflict angle θ ₂Traffic conflict during ∈ (30 °, 90 °) is the side direction conflict,

To satisfy conflict vehicle relative velocity v 〉=10m/s and conflict angle θ ₃∈ (90 °, 180 °) condition be the subtend conflict and,

With spacing D before and after satisfying on the same track _h≤ 5m and back vehicle speed conflict for knocking into the back with front truck speed difference DELTA v＞5m/s condition;

Use Vehicle Video-Capture Data Collector Video processing software, conflicted in the same way, the number of times of side direction conflict, subtend conflict and the conflict of knocking into the back, accumulative total is tried to achieve road section traffic volume conflict number of times C,

If the traffic conflict number of times C in step 4) highway section is greater than critical traffic conflict number of times τ, then this highway section is that an accident is easily sent out the highway section.