A regional dynamic perimeter control method for preventing queuing overflow of boundary links, comprising the following steps:
- dynamically dividing boundary links according to obtained traffic flow information of the boundary links to obtain a boundary link set with sufficient available storage space I(t) and a boundary link set with insufficient available storage space I(t);
- obtaining a critical accumulation of a region according to a preset Macroscopic Fundamental Diagram (MFD) model of the region, and estimating a predicted accumulation of the region in a next sampling period;
- and
- dynamically controlling a traffic flow operation of a regional boundary intersection according to a deviation between the predicted accumulation and the critical accumulation and each boundary link set, wherein
- when the deviation between the predicted accumulation and the critical accumulation of the region is zero, a boundary signal control is not changed;
- when the deviation is greater than zero, indicating that an input traffic flow of the regional road network needs to adopt a flow interception control strategy, the boundary road link set with sufficient available storage space is adopted for perimeter control, at this moment, according to the real-time traffic flow and the residual queuing space of the boundary links, a regional input traffic flow to be regulated is distributed to the boundary link set with sufficient available storage space I(t), wherein:
- the steps further include calculating the regional input traffic flow to be regulated in the boundary link with sufficient available storage space I(t) by adopting the following formula:
- si(t+1)=min{Σr∈I(t)hr(t)/S(t+1)hi(t),Qi−Ŷi(t+1)}
- where hi(t) represents a real-time input traffic flow of a boundary link i in the tth sampling period, Σhr(t) represents the sum of real-time input traffic flows of all road links in the boundary link set I(t) in the tth sampling period, Qi represents a maximum total number of receivable vehicles of the boundary link i, and Ŷi(t+1) represents a predicted value of queuing vehicles of the boundary link i in the t+Ith sampling period;
- and
- when the deviation is less than zero, indicating that the input traffic flow of the regional road network needs to adopt a drainage control strategy, the boundary link set with insufficient available storage space Ī(t) is adopted for perimeter control, at this moment, according to the number of lanes of the links, the regional input traffic flow to be regulated is distributed to the boundary link set with insufficient available storage space Ī(t), wherein:
- the steps further include calculating the regional input traffic flow to be regulated in the boundary link with insufficient available storage space Ī(t) by adopting the following formula:
- sv(t+1)=Σr∈I(t)nr/S(t+1)nv
- wherein, nv represents the number of lanes of a boundary link v, and Σv∈Ī(t)nv represents the sum of lanes of all road links in the boundary link set Ī(t);
- and
- converting, by utilizing the real-time flow of the boundary links of the region and available queuing space information, the deviation between the predicted accumulation and the critical accumulation of the region into a green light duration of a controlled boundary intersection, comprising:
- calculating a green light duration adjustment value of an input direction of the boundary link in a t+Ith sampling period:
- Δgi(t+1)=hi(t)/si(t+1)gi(t)
- wherein gi(t) represents a green light duration of an input flow direction of the boundary link i in the tth sampling period;
- then, converting the regional input traffic flow to be regulated of the boundary link into a signal timing parameter of a corresponding boundary intersection, and the specific update formula is as follows:
- gv(t+1)=gv(t)−sv(t+1)β
- wherein gv(t) represents a phase green light duration of an input direction of the boundary link v, and β represents a saturated time headway;
- and
- then, dynamically adjusting the signal timing parameter of the corresponding boundary intersection according to green light duration update formulas under different control scenarios to obtain a green light duration of an input direction of a boundary link in the next sampling period.