diff --git a/docs/lanes.md b/docs/lanes.md
index 00c1e4e7be..9a4a6662d9 100644
--- a/docs/lanes.md
+++ b/docs/lanes.md
@@ -120,11 +120,8 @@ wait slow down even more -- before any of this change, lanes on adjacent roads s
 	- make final Map serializable too
 		- useful to precompute sidewalk paths
 		- waiting on https://github.com/paholg/dimensioned/issues/31 to release
-		- cant easily serialize ordered float, so move away from it first?
-
 
 	- isolate vec2d
-	- turn's slope() and vecmath::normalized
 	- split out geometry crate again
 	- let ezgui stuff depend on it too
 	- also a polygon struct? for parcels and buildings
diff --git a/editor/Cargo.toml b/editor/Cargo.toml
index 652b1f4a75..377b62ce5f 100644
--- a/editor/Cargo.toml
+++ b/editor/Cargo.toml
@@ -23,4 +23,3 @@ sim = { path = "../sim" }
 structopt = "0.2"
 strum = "0.9.0"
 strum_macros = "0.9.0"
-vecmath = "0.3.1"
diff --git a/editor/src/main.rs b/editor/src/main.rs
index 2badc63f6e..a0af258003 100644
--- a/editor/src/main.rs
+++ b/editor/src/main.rs
@@ -21,7 +21,6 @@ extern crate structopt;
 extern crate strum;
 #[macro_use]
 extern crate strum_macros;
-extern crate vecmath;
 
 use ezgui::input::UserInput;
 use glutin_window::GlutinWindow;
diff --git a/editor/src/render/turn.rs b/editor/src/render/turn.rs
index 4ee14ad46e..6cb55e4839 100644
--- a/editor/src/render/turn.rs
+++ b/editor/src/render/turn.rs
@@ -13,7 +13,6 @@ use map_model::geometry;
 use render::{BIG_ARROW_TIP_LENGTH, TURN_ICON_ARROW_LENGTH, TURN_ICON_ARROW_THICKNESS,
              TURN_ICON_ARROW_TIP_LENGTH};
 use std::f64;
-use vecmath;
 
 #[derive(Debug)]
 pub struct DrawTurn {
@@ -27,23 +26,21 @@ pub struct DrawTurn {
 impl DrawTurn {
     pub fn new(map: &map_model::Map, turn: &map_model::Turn, offset_along_road: usize) -> DrawTurn {
         let offset_along_road = offset_along_road as f64;
-        let src_pt = map.get_r(turn.src).last_pt();
-        let dst_pt = map.get_r(turn.dst).first_pt();
-        let slope = vecmath::vec2_normalized([dst_pt.x() - src_pt.x(), dst_pt.y() - src_pt.y()]);
+        let src_pt = turn.line.pt1();
+        let dst_pt = turn.line.pt2();
+        let angle = turn.line.angle();
         let last_line = map.get_r(turn.src).last_line();
 
         // Start the distance from the intersection
         let icon_center = last_line
             .reverse()
             .unbounded_dist_along((offset_along_road + 0.5) * TURN_ICON_ARROW_LENGTH * si::M);
-        let icon_src = [
-            icon_center.x() - (TURN_ICON_ARROW_LENGTH / 2.0) * slope[0],
-            icon_center.y() - (TURN_ICON_ARROW_LENGTH / 2.0) * slope[1],
-        ];
-        let icon_dst = [
-            icon_center.x() + (TURN_ICON_ARROW_LENGTH / 2.0) * slope[0],
-            icon_center.y() + (TURN_ICON_ARROW_LENGTH / 2.0) * slope[1],
-        ];
+        let icon_src = icon_center
+            .project_away(TURN_ICON_ARROW_LENGTH / 2.0, angle.opposite())
+            .to_vec();
+        let icon_dst = icon_center
+            .project_away(TURN_ICON_ARROW_LENGTH / 2.0, angle)
+            .to_vec();
 
         let icon_circle = geometry::circle(
             icon_center.x(),
diff --git a/map_model/Cargo.toml b/map_model/Cargo.toml
index acada2faf0..97b91c915f 100644
--- a/map_model/Cargo.toml
+++ b/map_model/Cargo.toml
@@ -13,4 +13,3 @@ piston2d-graphics = "*"
 rand = "0.5.1"
 serde = "1.0"
 serde_derive = "1.0"
-vecmath = "0.3.1"
diff --git a/map_model/src/lib.rs b/map_model/src/lib.rs
index 00543f7435..b2c4546136 100644
--- a/map_model/src/lib.rs
+++ b/map_model/src/lib.rs
@@ -10,7 +10,6 @@ extern crate rand;
 extern crate serde;
 #[macro_use]
 extern crate serde_derive;
-extern crate vecmath;
 
 mod building;
 pub mod geometry;
diff --git a/map_model/src/turn.rs b/map_model/src/turn.rs
index 20045cb775..58f11d4df4 100644
--- a/map_model/src/turn.rs
+++ b/map_model/src/turn.rs
@@ -7,7 +7,6 @@ use Pt2D;
 use RoadID;
 use dimensioned::si;
 use std::f64;
-use vecmath;
 
 // TODO reconsider pub usize. maybe outside world shouldnt know.
 #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq, Serialize, Deserialize)]
@@ -49,12 +48,4 @@ impl Turn {
     pub fn length(&self) -> si::Meter<f64> {
         self.line.length()
     }
-
-    // TODO rethink this one
-    pub fn slope(&self) -> [f64; 2] {
-        vecmath::vec2_normalized([
-            self.line.pt2().x() - self.line.pt1().x(),
-            self.line.pt2().y() - self.line.pt1().y(),
-        ])
-    }
 }
diff --git a/sim/Cargo.toml b/sim/Cargo.toml
index 4913923ce6..75a05c5df7 100644
--- a/sim/Cargo.toml
+++ b/sim/Cargo.toml
@@ -15,4 +15,3 @@ piston2d-graphics = "*"
 rand = { version = "0.5.1", features = ["serde1"] }
 serde = "1.0"
 serde_derive = "1.0"
-vecmath = "0.3.1"
diff --git a/sim/src/lib.rs b/sim/src/lib.rs
index 99ab557f13..54c016a004 100644
--- a/sim/src/lib.rs
+++ b/sim/src/lib.rs
@@ -12,7 +12,6 @@ extern crate rand;
 extern crate serde;
 #[macro_use]
 extern crate serde_derive;
-extern crate vecmath;
 
 pub mod common;
 mod straw_intersections;
diff --git a/sim/src/straw_model.rs b/sim/src/straw_model.rs
index a6b466bdaa..7c41cbeabd 100644
--- a/sim/src/straw_model.rs
+++ b/sim/src/straw_model.rs
@@ -495,13 +495,9 @@ impl Sim {
         let mut cars = self.roads[r.0].get_draw_cars(&self, map);
         for c in &mut cars {
             if let Some(on) = self.cars[&c.id].waiting_for {
-                let slope = map.get_t(on.as_turn()).slope();
-                c.turn_arrow = Some([
-                    c.front.x() - (CAR_LENGTH / 2.0) * slope[0],
-                    c.front.y() - (CAR_LENGTH / 2.0) * slope[1],
-                    c.front.x(),
-                    c.front.y(),
-                ]);
+                let angle = map.get_t(on.as_turn()).line.angle();
+                let arrow_pt = c.front.project_away(CAR_LENGTH / 2.0, angle.opposite());
+                c.turn_arrow = Some([arrow_pt.x(), arrow_pt.y(), c.front.x(), c.front.y()]);
             }
         }
         cars