Problem Statement: Compare the total number and types of vehicular conflict points between a standard four-leg, two-way intersection and a single-lane four-leg roundabout. Explain the safety implications of the difference.

Problem Statement: An intersection has two phases. The lost time per phase ($l_i$) is 4 seconds. The flow ratio ($y_i$) for Phase 1 is 0.35, and for Phase 2 is 0.40. Calculate the total lost time ($L$), the sum of flow ratios ($Y$), and the optimal cycle length ($C_o$) using Webster's method.

Problem Statement: A vehicle approaches an intersection at 45 mph ($v = 66 \text{ ft/s}$). The yellow light duration ($Y$) is 4.0 seconds. The driver's perception-reaction time ($t_r$) is 1.0 second, and the comfortable deceleration rate ($a$) is 10 ft/s². The intersection is 40 ft wide ($W$), and the vehicle is 15 ft long ($L$). Determine the safe stopping distance ($X_s$) and the safe clearing distance ($X_c$). Does a dilemma zone exist?