The operation and design of signalized intersections involves tradeoffs between operational efficiency and safety for a variety of users, including motorists, pedestrians, and bicyclists. Additionally, the mix of vehicle types in the fleet sometimes requires special considerations. These concerns especially apply to the selection of curb radius at the corners, where right-turning vehicles operate close to pedestrians. Larger curb radii accommodate the swept paths of trucks and allow right turns to occur at higher speeds but may compromise safety and security for pedestrians by increasing the crossing distance and increasing the frequency of higher-speed turns. The authors collected right-turn vehicle speeds at 31 urban signalized intersection approaches in Texas with radii ranging from 15 to 70 ft. The authors calibrated a model to predict right-turn speeds as a function of site characteristics including curb radius, leading headway, vehicle type (car versus truck), maneuver of the preceding vehicle (through versus right turn), and signal indication (yellow or green). The analysis results indicate that right-turn speeds increase slightly with increasing radius, if the preceding vehicle proceeds through (rather than turning right) at the intersection, or if the signal indication is yellow rather than green. The calculated 85th percentile turning speed is generally higher than the assumed speed calculated using the radius of curvature equation. These trends should be considered if the intersection is expected to have notable volumes of pedestrians or trucks, as lower speeds are desirable for pedestrian safety, but larger radii may be necessary to accommodate turning trucks.

信号交叉路口的操作和设计需要在包括驾驶员，行人和骑自行车者在内的各种用户的操作效率和安全性之间进行权衡。另外，车队中车辆类型的混合有时需要特殊考虑。这些问题尤其适用于拐角处的路缘半径的选择，在这些拐角处，右转车辆靠近行人。较大的路缘半径可容纳卡车的后掠路径，并允许以较高的速度发生右转弯，但可能会通过增加交叉距离和增加高速转弯的频率而损害行人的安全性。作者收集了德克萨斯州31个城市信号交叉路口的右转车速，半径范围为15到70英尺。作者对模型进行了校准，以根据站点特征预测右转速度，这些特征包括路缘半径，前行车距，车辆类型（汽车相对于卡车），先前车辆的机动性（直通与右转）以及信号指示（黄色或黄色）。绿色）。分析结果表明，如果前车在交叉路口前行（而不是右转），或者信号指示为黄色而不是绿色，则右转速度会随半径的增加而略有增加。计算出的第85个百分位转弯速度通常高于使用曲率半径方程式计算出的假定速度。如果预计交叉路口有大量行人或卡车，则应考虑这些趋势，因为对于行人安全而言，较低的速度是可取的，