diff --git a/frontend/package-lock.json b/frontend/package-lock.json
index fe039ad..963f3b9 100644
--- a/frontend/package-lock.json
+++ b/frontend/package-lock.json
@@ -11,6 +11,7 @@
         "@babel/runtime": "^7.16.3",
         "@turf/bbox": "^6.5.0",
         "classnames": "^2.3.1",
+        "colormap": "^2.3.2",
         "downloadjs": "^1.4.7",
         "fomantic-ui-less": "^2.8.8",
         "immer": "^9.0.7",
@@ -3262,6 +3263,14 @@
       "integrity": "sha512-hUewv7oMjCp+wkBv5Rm0v87eJhq4woh5rSR+42YSQJKecCqgIqNkZ6lAlQms/BwHPJA5NKMRlpxPRv0n8HQW6g==",
       "dev": true
     },
+    "node_modules/colormap": {
+      "version": "2.3.2",
+      "resolved": "https://registry.npmjs.org/colormap/-/colormap-2.3.2.tgz",
+      "integrity": "sha512-jDOjaoEEmA9AgA11B/jCSAvYE95r3wRoAyTf3LEHGiUVlNHJaL1mRkf5AyLSpQBVGfTEPwGEqCIzL+kgr2WgNA==",
+      "dependencies": {
+        "lerp": "^1.0.3"
+      }
+    },
     "node_modules/commander": {
       "version": "2.20.3",
       "resolved": "https://registry.npmjs.org/commander/-/commander-2.20.3.tgz",
@@ -5389,6 +5398,11 @@
         "node": ">= 8"
       }
     },
+    "node_modules/lerp": {
+      "version": "1.0.3",
+      "resolved": "https://registry.npmjs.org/lerp/-/lerp-1.0.3.tgz",
+      "integrity": "sha1-oYyJaPkXiW3hXM/MKNVaa3Med24="
+    },
     "node_modules/less": {
       "version": "4.1.2",
       "resolved": "https://registry.npmjs.org/less/-/less-4.1.2.tgz",
@@ -11551,6 +11565,14 @@
       "integrity": "sha512-hUewv7oMjCp+wkBv5Rm0v87eJhq4woh5rSR+42YSQJKecCqgIqNkZ6lAlQms/BwHPJA5NKMRlpxPRv0n8HQW6g==",
       "dev": true
     },
+    "colormap": {
+      "version": "2.3.2",
+      "resolved": "https://registry.npmjs.org/colormap/-/colormap-2.3.2.tgz",
+      "integrity": "sha512-jDOjaoEEmA9AgA11B/jCSAvYE95r3wRoAyTf3LEHGiUVlNHJaL1mRkf5AyLSpQBVGfTEPwGEqCIzL+kgr2WgNA==",
+      "requires": {
+        "lerp": "^1.0.3"
+      }
+    },
     "commander": {
       "version": "2.20.3",
       "resolved": "https://registry.npmjs.org/commander/-/commander-2.20.3.tgz",
@@ -13150,6 +13172,11 @@
       "resolved": "https://registry.npmjs.org/klona/-/klona-2.0.5.tgz",
       "integrity": "sha512-pJiBpiXMbt7dkzXe8Ghj/u4FfXOOa98fPW+bihOJ4SjnoijweJrNThJfd3ifXpXhREjpoF2mZVH1GfS9LV3kHQ=="
     },
+    "lerp": {
+      "version": "1.0.3",
+      "resolved": "https://registry.npmjs.org/lerp/-/lerp-1.0.3.tgz",
+      "integrity": "sha1-oYyJaPkXiW3hXM/MKNVaa3Med24="
+    },
     "less": {
       "version": "4.1.2",
       "resolved": "https://registry.npmjs.org/less/-/less-4.1.2.tgz",
diff --git a/frontend/package.json b/frontend/package.json
index 172cfc5..5a0452f 100644
--- a/frontend/package.json
+++ b/frontend/package.json
@@ -10,6 +10,7 @@
     "@babel/runtime": "^7.16.3",
     "@turf/bbox": "^6.5.0",
     "classnames": "^2.3.1",
+    "colormap": "^2.3.2",
     "downloadjs": "^1.4.7",
     "fomantic-ui-less": "^2.8.8",
     "immer": "^9.0.7",
diff --git a/frontend/src/mapstyles/index.js b/frontend/src/mapstyles/index.js
index 7c468e2..d05942b 100644
--- a/frontend/src/mapstyles/index.js
+++ b/frontend/src/mapstyles/index.js
@@ -3,9 +3,50 @@ import _ from 'lodash'
 import bright from './bright.json'
 import positron from './positron.json'
 
+import viridisBase from 'colormap/res/res/viridis'
+
 export {bright, positron}
 export const baseMapStyles = {bright, positron}
 
+
+function simplifyColormap(colormap, maxCount = 16) {
+  const result = []
+  const step = Math.ceil(colormap.length / maxCount)
+  for (let i = 0; i < colormap.length;  i+= step) {
+    result.push(colormap[i])
+  }
+  return result
+}
+
+function rgbArrayToColor(arr) {
+      return ['rgb', ...arr.map(v => Math.round(v*255))]
+}
+
+export function colormapToScale(colormap, value, min, max) {
+  return [
+    'interpolate-hcl',
+    ['linear'],
+    value,
+    ...colormap.flatMap((v, i, a) => [
+      (i / (a.length - 1)) * (max - min) + min,
+      v,
+    ])
+  ]
+}
+
+export const viridis = simplifyColormap(viridisBase.map(rgbArrayToColor), 20);
+export const grayscale = ['#FFFFFF', '#000000']
+export const reds = [['rgba', 255, 0, 0, 0], ['rgba', 255, 0, 0, 1]]
+
+export function colorByCount(attribute = 'event_count', maxCount, colormap = viridis) {
+  return colormapToScale(
+    colormap,
+    ['case', ['to-boolean', ['get', attribute]], ['get', attribute], 0],
+    0,
+    maxCount
+  )
+}
+
 export function colorByDistance(attribute = 'distance_overtaker_mean', fallback = '#ABC') {
   return [
     'case',
diff --git a/frontend/src/pages/MapPage/LayerSidebar.tsx b/frontend/src/pages/MapPage/LayerSidebar.tsx
index c8aa5ff..25d8a72 100644
--- a/frontend/src/pages/MapPage/LayerSidebar.tsx
+++ b/frontend/src/pages/MapPage/LayerSidebar.tsx
@@ -1,8 +1,13 @@
 import React from 'react'
+import _ from 'lodash'
 import {connect} from 'react-redux'
-import {List, Select, Header, Checkbox} from 'semantic-ui-react'
+import {List, Select, Input, Divider, Checkbox} from 'semantic-ui-react'
 
-import * as mapConfigActions from 'reducers/mapConfig'
+import {
+  MapConfig,
+  setMapConfigFlag as setMapConfigFlagAction,
+  initialState as defaultMapConfig,
+} from 'reducers/mapConfig'
 
 const BASEMAP_STYLE_OPTIONS = [
   {value: 'positron', key: 'positron', text: 'Positron'},
@@ -17,8 +22,14 @@ const ROAD_ATTRIBUTE_OPTIONS = [
   {value: 'overtaking_event_count', key: 'overtaking_event_count', text: 'Event count'},
 ]
 
-function LayerSidebar({mapConfig, setMapConfigFlag}) {
-  const showUntagged = mapConfig?.obsRoads?.showUntagged ?? true
+function LayerSidebar({
+  mapConfig,
+  setMapConfigFlag,
+}: {
+  mapConfig: MapConfig
+  setMapConfigFlag: (flag: string, value: unknown) => void
+}) {
+  const {baseMap: {style}, obsRoads: {show, showUntagged, attribute, maxCount}} = mapConfig
 
   return (
     <div>
@@ -27,28 +38,60 @@ function LayerSidebar({mapConfig, setMapConfigFlag}) {
           <List.Header>Basemap Style</List.Header>
           <Select
             options={BASEMAP_STYLE_OPTIONS}
-            value={mapConfig?.baseMap?.style ?? 'positron'}
+            value={style}
             onChange={(_e, {value}) => setMapConfigFlag('baseMap.style', value)}
           />
         </List.Item>
-        <Header as='h4' dividing>OBS Roads</Header>
+        <Divider />
         <List.Item>
-          <Checkbox label='Show untagged roads' checked={showUntagged}
+          <Checkbox
+            checked={showUntagged}
             onChange={() => setMapConfigFlag('obsRoads.showUntagged', !showUntagged)}
+            label="Untagged roads"
+          />
+        </List.Item>
+        <Divider />
+        <List.Item>
+          <Checkbox
+            checked={show}
+            onChange={() => setMapConfigFlag('obsRoads.show', !show)}
+            label="OBS Roads"
           />
         </List.Item>
         <List.Item>
-          <List.Header style={{marginBlock: 8}}>Color based on</List.Header>
+          <List.Header>Color based on</List.Header>
           <Select
             fluid
             options={ROAD_ATTRIBUTE_OPTIONS}
-            value={mapConfig?.obsRoads?.attribute ?? 'distance_overtaker_mean'}
+            value={attribute}
             onChange={(_e, {value}) => setMapConfigFlag('obsRoads.attribute', value)}
           />
         </List.Item>
+        {attribute.endsWith('_count') ? (
+          <List.Item>
+            <List.Header>Maximum value</List.Header>
+            <Input
+              fluid
+              type="number"
+              value={maxCount}
+              onChange={(_e, {value}) => setMapConfigFlag('obsRoads.maxCount', value)}
+            />
+          </List.Item>
+        ) : null}
       </List>
     </div>
   )
 }
 
-export default connect((state) => ({mapConfig: state.mapConfig}), mapConfigActions)(LayerSidebar)
+export default connect(
+  (state) => ({
+    mapConfig: _.merge(
+      {},
+      defaultMapConfig,
+      (state as any).mapConfig as MapConfig,
+      //
+    ),
+  }),
+  {setMapConfigFlag: setMapConfigFlagAction}
+  //
+)(LayerSidebar)
diff --git a/frontend/src/pages/MapPage/index.tsx b/frontend/src/pages/MapPage/index.tsx
index 9b9eae1..8d6be94 100644
--- a/frontend/src/pages/MapPage/index.tsx
+++ b/frontend/src/pages/MapPage/index.tsx
@@ -7,13 +7,12 @@ import {connect} from 'react-redux'
 
 import {Page, Map} from 'components'
 import {useConfig} from 'config'
-import {colorByDistance} from 'mapstyles'
+import {colorByDistance, colorByCount, reds} from 'mapstyles'
 
 import RoadInfo from './RoadInfo'
 import LayerSidebar from './LayerSidebar'
 import styles from './styles.module.less'
 
-
 const untaggedRoadsLayer = {
   id: 'obs_roads_untagged',
   type: 'line',
@@ -25,25 +24,9 @@ const untaggedRoadsLayer = {
     'line-join': 'round',
   },
   paint: {
-    'line-width': [
-      'interpolate',
-      ['exponential', 1.5],
-      ['zoom'],
-      12,
-      2,
-      17,
-      2,
-    ],
-    'line-color': "#ABC",
-    'line-opacity': [
-      'interpolate',
-      ['linear'],
-      ['zoom'],
-      14,
-      0,
-      15,
-      1,
-    ],
+    'line-width': ['interpolate', ['exponential', 1.5], ['zoom'], 12, 2, 17, 2],
+    'line-color': '#ABC',
+    'line-opacity': ['interpolate', ['linear'], ['zoom'], 14, 0, 15, 1],
     'line-offset': [
       'interpolate',
       ['exponential', 1.5],
@@ -57,14 +40,23 @@ const untaggedRoadsLayer = {
   minzoom: 12,
 }
 
-const getRoadsLayer = attribute => produce(untaggedRoadsLayer, draft => {
-  draft.id = 'obs_roads_normal'
-  draft.filter = draft.filter[1] // remove '!'
-  draft.paint['line-width'][6] = 6
-  draft.paint['line-color'] = colorByDistance(attribute)
-  draft.paint['line-opacity'][3] = 12
-  draft.paint['line-opacity'][5] = 13
-})
+const getRoadsLayer = (colorAttribute, maxCount) =>
+  produce(untaggedRoadsLayer, (draft) => {
+    draft.id = 'obs_roads_normal'
+    if (colorAttribute.endsWith('_count')) {
+      delete draft.filter
+    } else {
+      draft.filter = draft.filter[1] // remove '!'
+    }
+      draft.paint['line-width'][6] = 6 // scale bigger on zoom
+    draft.paint['line-color'] = colorAttribute.startsWith('distance_')
+      ? colorByDistance(colorAttribute)
+      : colorAttribute.endsWith('_count')
+      ? colorByCount(colorAttribute, maxCount, reds)
+      : '#DDD'
+    draft.paint['line-opacity'][3] = 12
+    draft.paint['line-opacity'][5] = 13
+  })
 
 function MapPage({mapConfig}) {
   const {obsMapSource} = useConfig() || {}
@@ -89,7 +81,11 @@ function MapPage({mapConfig}) {
 
   const showUntagged = mapConfig?.obsRoads?.showUntagged ?? true
   const roadsLayerColorAttribute = mapConfig?.obsRoads?.attribute ?? 'distance_overtaker_mean'
-  const roadsLayer = useMemo(() => getRoadsLayer(roadsLayerColorAttribute ), [roadsLayerColorAttribute ])
+  const roadsLayerMaxCount = mapConfig?.obsRoads?.maxCount ?? 20
+  const roadsLayer = useMemo(() => getRoadsLayer(roadsLayerColorAttribute, roadsLayerMaxCount), [
+    roadsLayerColorAttribute,
+    roadsLayerMaxCount,
+  ])
 
   if (!obsMapSource) {
     return null
@@ -98,7 +94,11 @@ function MapPage({mapConfig}) {
   return (
     <Page fullScreen>
       <div className={styles.mapContainer}>
-        {layerSidebar && <div className={styles.mapSidebar}><LayerSidebar /></div>}
+        {layerSidebar && (
+          <div className={styles.mapSidebar}>
+            <LayerSidebar />
+          </div>
+        )}
         <div className={styles.map}>
           <Map viewportFromUrl onClick={onClick}>
             <Button
diff --git a/frontend/src/reducers/mapConfig.ts b/frontend/src/reducers/mapConfig.ts
index 2c468b4..b20de37 100644
--- a/frontend/src/reducers/mapConfig.ts
+++ b/frontend/src/reducers/mapConfig.ts
@@ -2,25 +2,48 @@ import produce from 'immer'
 import _ from 'lodash'
 
 type BaseMapStyle = 'positron' | 'bright'
-type MapConfigState  = {
+
+type RoadAttribute =
+  | 'distance_overtaker_mean'
+  | 'distance_overtaker_min'
+  | 'distance_overtaker_max'
+  | 'distance_overtaker_median'
+  | 'overtaking_event_count'
+
+export type MapConfig = {
   baseMap: {
     style: BaseMapStyle
   }
+  obsRoads:{
+    show: boolean
+    showUntagged: boolean
+    attribute: RoadAttribute
+    maxCount: number
+  }
 }
 
-const initialState: MapConfigState = {
+export const initialState: MapConfig = {
   baseMap: {
     style: 'positron',
   },
+  obsRoads: {
+    show: true,
+    showUntagged: true,
+    attribute: 'distance_overtaker_median',
+    maxCount: 20,
+  },
 }
 
-export function setMapConfigFlag(flag: string, value: unknown) {
-  return {type: 'MAPCONFIG.SET_FLAG', payload: {flag, value}}
+type MapConfigAction =
+  {type: 'MAP_CONFIG.SET_FLAG', payload: {flag: string, value: any}}
+
+export function setMapConfigFlag(flag: string, value: unknown): MapConfigAction {
+  return {type: 'MAP_CONFIG.SET_FLAG', payload: {flag, value}}
 }
 
-export default function mapConfigReducer(state = initialState, action) {
+export default function mapConfigReducer(state: MapConfig = initialState, action: MapConfigAction) {
   switch (action.type) {
-    case 'MAPCONFIG.SET_FLAG':
+    case 'MAP_CONFIG.SET_FLAG':
       return produce(state, draft => {
         _.set(draft, action.payload.flag, action.payload.value)
       })