Consider two flow$-$density relations for sections of Route $1,$ with curve I defining sections $1($from I$-95$ ramp to $193)$ and $3($beyond $410),$ and curve II defining section $2($UM area between $193$ and $410).$ The traffic characteristics of each section is represented with $($S$1,$ D$1),($S$2,$ D$2),($S$3,$ D$3).$ Section $4($S$4,$ D$4)$ is defined as part of section $1$ right before $193.$