Travel time prediction

Táto práca sa zaoberá predikciou dojazdových dôb vozidiel na cestných komunikáciách založenej na metódach strojového učenia. Je v nej rozobraná teória týkajúca sa dojazdových dôb a jednotlivé vedecké práce, ktoré sa venujú tejto problematike. V práci je vypracovaná analýza reálnych dát týkajúcich sa dojazdových dôb a sú navrhnuté príznaky, ktoré sú následne použité na tvorbu predikčných modelov. V rámci diplomovej práce bol navrhnutý a implementovaný komplexný predikčný systém, ktorého funkčnosť bola overená v praxi.This thesis discusses travel time prediction of vehicles on roads based on the methods of machine learning. It describes theory of travel times and summarizes scientific papers dealing with this topic. Within the thesis, analysis of real travel time data was done and the features to be used in prediction models were engineered. Finally, the complex prediction system was designed and implemented and has been tested in production environment.

Real-Time Short-Term Travel Time Prediction

Real-time short-term travel time prediction is a critical component of the Intelligent Transportation System (ITS) and an important element of the Advanced Traveler Information System (ATIS). Accurate and reliable travel time prediction enables both user and system controller to be well informed of the likely future conditions on roadways, so that pre-trip plans and traffic control strategies can be made accordingly in order to reduce travel time and relieve traffic congestion. With these travel time predictions, roads may be used more efficiently with better overall network performance. This research will study short-term travel time prediction for freeway applications using various sources of real time travel time data. The integrated prediction model proposed here will put emphasis on travel time prediction under various traffic and weather scenarios and especially inclement weather conditions

Short-Term Travel Time Prediction on Freeways

Short-term travel time prediction supports the implementation of proactive traffic management and control strategies to alleviate if not prevent congestion and enable rational route choices and traffic mode selections to enhance travel mobility and safety. Over the last decade, Bluetooth technology has been increasingly used in collecting travel time data due to the technology’s advantages over conventional detection techniques in terms of direct travel time measurement, anonymous detection, and cost-effectiveness. However, similar to many other Automatic Vehicle Identification (AVI) technologies, Bluetooth technology has some limitations in measuring travel time information including 1) Bluetooth technology cannot associate travel time measurements with different traffic streams or facilities, therefore, the facility-specific travel time information is not directly available from Bluetooth measurements; 2) Bluetooth travel time measurements are influenced by measurement lag, because the travel time associated with vehicles that have not reached the downstream Bluetooth detector location cannot be taken at the instant of analysis. Freeway sections may include multiple distinct traffic stream (i.e., facilities) moving in the same direction of travel under a number of scenarios including: (1) a freeway section that contain both a High Occupancy Vehicle (HOV) or High Occupancy Toll (HOT) lane and several general purpose lanes (GPL); (2) a freeway section with a nearby parallel service roadway; (3) a freeway section in which there exist physically separated lanes (e.g. express versus collector lanes); or (4) a freeway section in which a fraction of the lanes are used by vehicles to access an off ramp. In this research, two different methods were proposed in estimating facility-specific travel times from Bluetooth measurements. Method 1 applies the Anderson-Darling test in matching the distribution of real-time Bluetooth travel time measurements with reference measurements. Method 2 first clusters the travel time measurements using the K-means algorithm, and then associates the clusters with facilities using traffic flow model. The performances of these two proposed methods have been evaluated against a Benchmark method using simulation data. A sensitivity analysis was also performed to understand the impacts of traffic conditions on the performance of different models. Based on the results, Method 2 is recommended when the physical barriers or law enforcement prevent drivers from freely switching between the underlying facilities; however, when the roadway functions as a self-correcting system allowing vehicles to freely switching between underlying facilities, the Benchmark method, which assumes one facility always operating faster than the other facility, is recommended for application. The Bluetooth travel time measurement lag leads to delayed detection of traffic condition variations and travel time changes, especially during congestion and transition periods or when consecutive Bluetooth detectors are placed far apart. In order to alleviate the travel time measurement lag, this research proposed to use non-lagged Bluetooth measurements (e.g., the number of repetitive detections for each vehicle and the time a vehicle spent in the detection zone) for inferring traffic stream states in the vicinity of the Bluetooth detectors. Two model structures including the analytical model and the statistical model have been proposed to estimate the traffic conditions based on non-lagged Bluetooth measurements. The results showed that the proposed RUSBoost classification tree achieved over 94% overall accuracy in predicting traffic conditions as congested or uncongested. When modeling traffic conditions as three traffic states (i.e., the free-flow state, the transition state, and the congested state) using the RUSBoost classification tree, the overall accuracy was 67.2%; however, the accuracy in predicting the congested traffic state was improved from 84.7% of the two state model to 87.7%. Because traffic state information enables the travel time prediction model to more timely detect the changes in traffic conditions, both the two-state model and the three-state model have been evaluated in developing travel time prediction models in this research. The Random Forest model was the main algorithm adopted in training travel time prediction models using both travel time measurements and inferred traffic states. Using historical Bluetooth data as inputs, the model results proved that the inclusion of traffic states information consistently lead to better travel time prediction results in terms of lower root mean square errors (improved by over 11%), lower 90th percentile absolute relative error ARE (improved by over 12%), and lower standard deviations of ARE (improved by over 15%) compared to other model structures without traffic states as inputs. In addition, the impact of traffic state inclusion on travel time prediction accuracy as a function of Bluetooth detector spacing was also examined using simulation data. The results showed that the segment length of 4~8 km is optimal in terms of the improvement from using traffic state information in travel time prediction models

Integrated Traffic and Communication Performance Evaluation of an Intelligent Vehicle Infrastructure Integration (VII) System for Online Travel Time Prediction

This paper presents a framework for online highway travel time prediction using traffic measurements that are likely to be available from Vehicle Infrastructure Integration (VII) systems, in which vehicle and infrastructure devices communicate to improve mobility and safety. In the proposed intelligent VII system, two artificial intelligence (AI) paradigms, namely Artificial Neural Networks (ANN) and Support Vector Regression (SVR), are used to determine future travel time based on such information as current travel time, VII-enabled vehicles’ flow and density. The development and performance evaluation of the VII-ANN and VII-SVR frameworks, in both of the traffic and communications domains, were conducted, using an integrated simulation platform, for a highway network in Greenville, South Carolina. Specifically, the simulation platform allows for implementing traffic surveillance and management methods in the traffic simulator PARAMICS, and for evaluating different communication protocols and network parameters in the communication network simulator, ns-2. The study’s findings reveal that the designed communications system was capable of supporting the travel time prediction functionality. They also demonstrate that the travel time prediction accuracy of the VII-AI framework was superior to a baseline instantaneous travel time prediction algorithm, with the VII-SVR model slightly outperforming the VII-ANN model. Moreover, the VII-AI framework was shown to be capable of performing reasonably well during non-recurrent congestion scenarios, which traditionally have challenged traffic sensor-based highway travel time prediction methods

Travel Time Prediction Based on Raw GPS Data

Aja planeerimine on muutunud aina olulisemaks üha kiireneva elutempoga ühiskonnas. Üheks oluliseks komponendiks aja planeerimisel on võimalikult täpselt hinnata, kui palju aega kulub ühest kohast teise liikumiseks. Käesolev magistritöö on valminud koostöös Boltiga, mis on üks suurimaid sõidujagamisteenust pakkuvaid ettevõtteid. Sõiduaja ennustamine tooreste GPS andmete põhjal nõuab suures koguses andmete eeltöötlemist, kasutades seejuures väliseid andmekogusid, et siduda tooreid GPS andmeid ümbritseva keskkonnaga. Käesolevas töös käsitletakse kõiki vajaminevaid eeltöötlemise samme, millest moodustub terviklik meetod sõiduaja ennustamiseks töötlemata GPS andmete põhjal. Meetodi efektiivsuse valideerimiseks on seda võrreldud kahe laialdaselt kasutu-ses oleva meetodiga.With the ever growing pace of our everyday lives, time planning has gained a lot of im-portance. One of the key factors for time planning is to estimate the duration of moving from one place to another. Therefore, travel time prediction has become essential part of any logistics based business. This thesis is conducted in collaboration with Bolt, which is one of the leading ride hailing companies. This thesis is describing route based travel time prediction algorithm based on raw GPS data. The goal is to analyze each of the pre-processing steps and to develop a coherent method to predict arrival time based on GPS input data supplied by Bolt. Furthermore, route based method described in this thesis is validated by comparing it to two well-known and established methods