A new four-lane divided rural arterial highway is being designed. The design standards specify the following cross-section elements:

• Travel lanes: $4$ lanes at $3.6 \text{ m}$ each.
• Median: A flush median of $5.0 \text{ m}$ width.
• Shoulders: Outside (right) shoulders of $3.0 \text{ m}$ each, and inside (left) shoulders of $1.5 \text{ m}$ each.
• Side slopes: The road is in a fill section, requiring side slopes of $4:1$ (Horizontal:Vertical). The average fill height is $2.5 \text{ m}$.
• Ditches/Clearance: An additional $3.0 \text{ m}$ beyond the toe of the slope on each side is required for utility clearance and fence lines.

Calculate the minimum total Right-of-Way (ROW) width required for this highway cross-section.

A two-lane undivided highway has a total pavement width of $7.2 \text{ m}$. To ensure adequate surface drainage, a straight-line cross slope (camber) of $2.5\%$ ($0.025$) is applied, draining outward from the centerline crown to the edges. Calculate the elevation difference between the centerline crown and the edge of the pavement.

A rural two-lane highway with a design speed of $90 \text{ km/h}$ and an Average Daily Traffic (ADT) of $4000$ vehicles per day has a fill slope of $1:6$. According to the AASHTO Roadside Design Guide, the required clear zone distance for these parameters is $9.0 \text{ meters}$, measured from the edge of the traveled way. The current cross-section has a $2.0 \text{ m}$ paved shoulder. A utility company wants to install wooden utility poles $6.0 \text{ m}$ from the edge of the traveled way. Determine if this placement is acceptable.

An existing two-lane urban arterial is experiencing severe congestion and is slated for expansion to four lanes with a raised median. The existing ROW is $20 \text{ meters}$, but the new cross-section requires a minimum of $35 \text{ meters}$. The corridor is lined with historic commercial buildings, some of which sit right on the existing ROW line. Analyze the engineering, economic, and social challenges of this expansion.

Compare the use of a parabolic (curved) camber versus a straight-line (roof-tent) camber. Why is a straight-line camber almost universally preferred for modern high-speed multilane highways (often utilizing concrete), while parabolic camber is sometimes seen in older urban streets or flexible pavements?