Traffic Flow Data Jan to June 2020 SDCC

<div><div><font face='Calibri, sans-serif' size='3'>SDCC Traffic Congestion Saturation Flow Data for January to June 2020. Traffic volumes, traffic saturation, and congestion data for sites across South Dublin County. Used by traffic management to control stage timings on junctions. It is recommended that this dataset is read in conjunction with the ‘Traffic Data Site Names SDCC’ dataset.</font></div><div><font face='Calibri, sans-serif' size='3'>A detailed description of each column heading can be referenced below;</font></div><div><font face='Calibri, sans-serif' size='3'><b>scn:</b> Site Serial number</font></div><div><font face='Calibri, sans-serif' size='3'><b>region: </b>A group of Nodes that are operated under SCOOT control at the same common cycle time. Normally these will be nodes between which co-ordination is desirable. Some of the nodes may be double cycling at half of the region cycle time.</font></div><div><font face='Calibri, sans-serif' size='3'><b>system:</b> SCOOT STC UTC (UTC-MX)</font></div><div><font face='Calibri, sans-serif' size='3'><b>locn:</b> Locations</font></div><div><font face='Calibri, sans-serif' size='3'><b>site:</b> Site numbers</font></div><div><div style='font-family:Calibri, sans-serif; font-size:medium;'><b>day:</b> Days of the week Monday to Sunday. Abbreviations; MO,TU,WE,TH,FR,SA,SU.</div><div style='font-family:Calibri, sans-serif; font-size:medium;'><b>date:</b> Reflects correct actual Date of when data was collected.</div><div style='font-family:Calibri, sans-serif; font-size:medium;'><b>start_time:</b> NOTE - Please ignore the date displayed in this column. The actual data collection date is correctly displayed in the 'date' column. <i>The date displayed here is the date of when report was run and extracted from the system, but correctly reflects start time of 15 minute intervals.</i> </div><div style='font-family:Calibri, sans-serif; font-size:medium;'><b>end_time:</b> End time of 15 minute intervals.</div></div><div><font face='Calibri, sans-serif' size='3'><b>flow:</b> A representation of demand (flow) for each link built up over several minutes by the SCOOT model. SCOOT has two profiles:</font></div><div><font face='Calibri, sans-serif' size='3'>(1) Short – Raw data representing the actual values over the previous few minutes</font></div><div><font face='Calibri, sans-serif' size='3'>(2) Long – A smoothed average of values over a longer period</font></div><div><font face='Calibri, sans-serif' size='3'>SCOOT will choose to use the appropriate profile depending on a number of factors.</font></div><div><font face='Calibri, sans-serif' size='3'><b>flow_pc:</b> Same as above ref PC SCOOT</font></div><div><font face='Calibri, sans-serif' size='3'><b>cong:</b> Congestion is directly measured from the detector. If the detector is placed beyond the normal end of queue in the street it is rarely covered by stationary traffic, except of course when congestion occurs. If any detector shows standing traffic for the whole of an interval this is recorded. The number of intervals of congestion in any cycle is also recorded.</font></div><div><font face='Calibri, sans-serif' size='3'>The percentage congestion is calculated from:</font></div><div><font face='Calibri, sans-serif' size='3'>No of congested intervals x 4 x 100 cycle time in seconds.</font></div><div><font face='Calibri, sans-serif' size='3'>This percentage of congestion is available to view and more importantly for the optimisers to take into account.</font></div><div><font face='Calibri, sans-serif' size='3'><b>cong_pc:</b> Same as above ref PC SCOOT</font></div><div><font face='Calibri, sans-serif' size='3'><b>dsat:</b> The ratio of the demand flow to the maximum possible discharge flow, i.e. it is the ratio of the demand to the discharge rate (Saturation Occupancy) multiplied by the duration of the effective green time. The Split optimiser will try to minimise the maximum degree of saturation on links approaching the node.</font></div><div><font face='Calibri, sans-serif' size='3'><br /></font></div><div><font face='Calibri, sans-serif' size='3'><br /></font></div><div style='font-family:Calibri, sans-serif; font-size:medium;'><br /></div></div><div><span style='font-family:Calibri, sans-serif;'><font size='3'><br /></font></span></div><div><span style='font-family:Calibri, sans-serif;'><font size='3'><br /></font></span></div>2020年1月至6月SDCC交通拥堵与通行饱和流量数据集。本数据集涵盖都柏林郡南部（South Dublin County，简称SDCC）全域各监测点位的交通流量、交通饱和度及拥堵状况数据，供交通管理部门调控交叉口信号灯配时方案。建议结合《SDCC交通数据点位名称（Traffic Data Site Names SDCC）》数据集一同使用本数据集。 各字段表头的详细说明如下： scn：点位序列号（Site Serial number） region：以相同公共周期时长受信号控制与优化技术（Signal Control and Optimisation Technique，简称SCOOT）管控的交叉口节点群组。通常此类群组内的节点需实现协调控制，部分节点可能以区域周期一半的时长进行双周期运行。 system：SCOOT STC UTC（UTC-MX） locn：点位位置（Locations） site：点位编号（Site numbers） day：星期时段，涵盖周一至周日，缩写为MO、TU、WE、TH、FR、SA、SU。 date：数据采集的实际日期。 start_time：注意：请忽略本字段中的日期信息，实际数据采集日期已在date字段中准确标注。本字段显示的日期为报告生成并从系统导出的日期，但本字段准确记录了15分钟统计时段的起始时间。 end_time：15分钟统计时段的结束时间。 flow：SCOOT模型基于数分钟内的交通数据生成的各路段通行需求（流量）表征值。SCOOT包含两种数据剖面： （1）短期剖面：基于前数分钟的原始实测数据生成的实际数值 （2）长期剖面：基于更长时段的数据平滑平均后生成的数值 SCOOT将根据多种因素选择适配的数据剖面。 flow_pc：含义同flow，参考SCOOT的PC指标。 cong：拥堵程度由检测器直接检测得到。若检测器安装于道路排队长度常规终点以外的位置，通常不会检测到静止车流，仅在发生拥堵时例外。若某一统计时段内检测器全程检测到静止车流，则记录为拥堵时段，同时记录单个信号周期内的拥堵时段总数。 拥堵百分比计算公式如下： 拥堵百分比=（拥堵时段总数 ×4 ×100）÷ 信号周期时长（单位：秒） 该拥堵百分比可用于查看，更重要的是可被信号优化算法纳入考量。 cong_pc：含义同cong，参考SCOOT的PC指标。 dsat：通行需求流量与最大可能放行流量的比值，即需求流量与放行速率（饱和占有率，Saturation Occupancy）的乘积乘以有效绿灯时长。信号配时优化模块将尽可能降低交叉口进口路段的最大饱和度。