diff --git a/Chapter03/src/analyze.rs b/Chapter03/src/analyze.rs
index 6e74684..bb084d6 100644
--- a/Chapter03/src/analyze.rs
+++ b/Chapter03/src/analyze.rs
@@ -13,6 +13,7 @@ use std::fs::File;
 use std::io::{self, Read, Write, BufRead, BufReader};
 use std::io::prelude::*;
 
+#[derive(Clone)]
 struct Trip {
    dst: u64,
    up: f64,
@@ -27,6 +28,7 @@ fn main()
    let mut jerk = 0.0;
    let mut prev_est: Option<ElevatorState> = None;
    let mut dst_timing: Vec<Trip> = Vec::new();
+   let mut start_location = 0.0;
    for line in simlog.lines() {
       let l = line.unwrap();
       match esp.clone() {
@@ -36,13 +38,13 @@ fn main()
          },
          Some(esp) => {
             let (est, dst): (ElevatorState,u64) = serde_json::from_str(&l).unwrap();
-            if dst_timing.len()==0 || dst_timing[0].dst != dst {
+            let dl = dst_timing.len();
+            if dst_timing.len()==0 || dst_timing[dl-1].dst != dst {
                dst_timing.push(Trip { dst:dst, up:0.0, down:0.0 });
             }
 
             if let Some(prev_est) = prev_est {
                let dt = est.timestamp - prev_est.timestamp;
-               let dl = dst_timing.len();
                if est.velocity > 0.0 {
                   dst_timing[dl-1].up += dt;
                } else {
@@ -53,6 +55,8 @@ fn main()
                if jerk.abs() > 0.22 {
                   panic!("jerk is outside of acceptable limits: {} {:?}", jerk, est)
                }
+            } else {
+               start_location = est.location;
             }
             if est.acceleration.abs() > 2.2 {
                panic!("acceleration is outside of acceptable limits: {:?}", est)
@@ -61,8 +65,6 @@ fn main()
                panic!("velocity is outside of acceptable limits: {:?}", est)
             }
             prev_est = Some(est);
-
-
          }
       }
    }
@@ -70,7 +72,7 @@ fn main()
    //elevator should not backup
    let mut total_time = 0.0;
    let mut total_direct = 0.0;
-   for trip in dst_timing
+   for trip in dst_timing.clone()
    {
       total_time += (trip.up + trip.down);
       if trip.up > trip.down {
@@ -83,6 +85,29 @@ fn main()
       panic!("elevator back up is too common: {}", total_direct / total_time)
    }
 
-   //trips should finish within 20% of theoretical limit
 
+   //trips should finish within 20% of theoretical limit
+   let MAX_JERK = 0.2;
+   let MAX_ACCELERATION = 2.0;
+   let MAX_VELOCITY = 5.0;
+
+   let mut trip_start_location = start_location;
+   let mut theoretical_time = 0.0;
+   let floor_height = esp.unwrap().floor_height;
+   for trip in dst_timing.clone()
+   {
+      let next_floor = (trip.dst as f64) * floor_height;
+      let d = (trip_start_location - next_floor).abs();
+      theoretical_time += (
+         2.0*(MAX_ACCELERATION / MAX_JERK) +
+         2.0*(MAX_JERK / MAX_ACCELERATION) +
+         d / MAX_VELOCITY
+      );
+      trip_start_location = next_floor;
+   }
+   if total_time > (theoretical_time * 1.2) {
+      panic!("elevator moves to slow {} {}", total_time, theoretical_time * 1.2)
+   }
+
+   println!("All simulation checks passing.");
 }