diff --git a/examples/content_types/src/main.rs b/examples/content_types/src/main.rs
index c8cd7d90..d9f76d27 100644
--- a/examples/content_types/src/main.rs
+++ b/examples/content_types/src/main.rs
@@ -9,33 +9,37 @@ extern crate serde_derive;
 #[cfg(test)] mod tests;
 
 use rocket::Request;
-use rocket::http::ContentType;
 use rocket::response::content;
 
 #[derive(Debug, Serialize, Deserialize)]
 struct Person {
     name: String,
-    age: i8,
+    age: u8,
 }
 
-// This shows how to manually serialize some JSON, but in a real application,
-// we'd use the JSON contrib type.
+// In a `GET` request and all other non-payload supporting request types, the
+// preferred media type in the Accept header is matched against the `format` in
+// the route attribute.
 #[get("/<name>/<age>", format = "application/json")]
-fn hello(content_type: ContentType, name: String, age: i8) -> content::JSON<String> {
-    let person = Person {
-        name: name,
-        age: age,
-    };
+fn get_hello(name: String, age: u8) -> content::JSON<String> {
+    // In a real application, we'd use the JSON contrib type.
+    let person = Person { name: name, age: age, };
+    content::JSON(serde_json::to_string(&person).unwrap())
+}
 
-    println!("ContentType: {}", content_type);
+// In a `POST` request and all other payload supporting request types, the
+// content type is matched against the `format` in the route attribute.
+#[post("/<age>", format = "text/plain", data = "<name>")]
+fn post_hello(age: u8, name: String) -> content::JSON<String> {
+    let person = Person { name: name, age: age, };
     content::JSON(serde_json::to_string(&person).unwrap())
 }
 
 #[error(404)]
 fn not_found(request: &Request) -> content::HTML<String> {
-    let html = match request.content_type() {
-        Some(ref ct) if !ct.is_json() => {
-            format!("<p>This server only supports JSON requests, not '{}'.</p>", ct)
+    let html = match request.format() {
+        Some(ref mt) if !mt.is_json() && !mt.is_plain() => {
+            format!("<p>'{}' requests are not supported.</p>", mt)
         }
         _ => format!("<p>Sorry, '{}' is an invalid path! Try \
                  /hello/&lt;name&gt;/&lt;age&gt; instead.</p>",
@@ -47,7 +51,7 @@ fn not_found(request: &Request) -> content::HTML<String> {
 
 fn main() {
     rocket::ignite()
-        .mount("/hello", routes![hello])
+        .mount("/hello", routes![get_hello, post_hello])
         .catch(errors![not_found])
         .launch();
 }
diff --git a/examples/content_types/src/tests.rs b/examples/content_types/src/tests.rs
index b7b0f254..5e9f5e85 100644
--- a/examples/content_types/src/tests.rs
+++ b/examples/content_types/src/tests.rs
@@ -1,14 +1,16 @@
 use super::rocket;
 use super::serde_json;
 use super::Person;
-use rocket::http::{ContentType, Method, Status};
+use rocket::http::{Accept, ContentType, Header, MediaType, Method, Status};
 use rocket::testing::MockRequest;
 
-fn test(uri: &str, content_type: ContentType, status: Status, body: String) {
+fn test<H>(method: Method, uri: &str, header: H, status: Status, body: String)
+    where H: Into<Header<'static>>
+{
     let rocket = rocket::ignite()
-        .mount("/hello", routes![super::hello])
+        .mount("/hello", routes![super::get_hello, super::post_hello])
         .catch(errors![super::not_found]);
-    let mut request = MockRequest::new(Method::Get, uri).header(content_type);
+    let mut request = MockRequest::new(method, uri).header(header);
     let mut response = request.dispatch_with(&rocket);
 
     assert_eq!(response.status(), status);
@@ -17,24 +19,29 @@ fn test(uri: &str, content_type: ContentType, status: Status, body: String) {
 
 #[test]
 fn test_hello() {
-    let person = Person {
-        name: "Michael".to_string(),
-        age: 80,
-    };
+    let person = Person { name: "Michael".to_string(), age: 80, };
     let body = serde_json::to_string(&person).unwrap();
-    test("/hello/Michael/80", ContentType::JSON, Status::Ok, body);
+    test(Method::Get, "/hello/Michael/80", Accept::JSON, Status::Ok, body.clone());
+    test(Method::Get, "/hello/Michael/80", Accept::Any, Status::Ok, body.clone());
+
+    // No `Accept` header is an implicit */*.
+    test(Method::Get, "/hello/Michael/80", ContentType::XML, Status::Ok, body);
+
+    let person = Person { name: "".to_string(), age: 99, };
+    let body = serde_json::to_string(&person).unwrap();
+    test(Method::Post, "/hello/99", ContentType::Plain, Status::Ok, body);
 }
 
 #[test]
 fn test_hello_invalid_content_type() {
-    let body = format!("<p>This server only supports JSON requests, not '{}'.</p>",
-                       ContentType::HTML);
-    test("/hello/Michael/80", ContentType::HTML, Status::NotFound, body);
+    let b = format!("<p>'{}' requests are not supported.</p>", MediaType::HTML);
+    test(Method::Get, "/hello/Michael/80", Accept::HTML, Status::NotFound, b.clone());
+    test(Method::Post, "/hello/80", ContentType::HTML, Status::NotFound, b);
 }
 
 #[test]
 fn test_404() {
     let body = "<p>Sorry, '/unknown' is an invalid path! Try \
                 /hello/&lt;name&gt;/&lt;age&gt; instead.</p>";
-    test("/unknown", ContentType::JSON, Status::NotFound, body.to_string());
+    test(Method::Get, "/unknown", Accept::JSON, Status::NotFound, body.to_string());
 }
diff --git a/lib/Cargo.toml b/lib/Cargo.toml
index 3d55342f..093fb60c 100644
--- a/lib/Cargo.toml
+++ b/lib/Cargo.toml
@@ -28,7 +28,7 @@ state = "0.2"
 time = "0.1"
 memchr = "1"
 base64 = "0.4"
-smallvec = "0.3"
+smallvec = { git = "https://github.com/SergioBenitez/rust-smallvec" }
 pear = "0.0.8"
 pear_codegen = "0.0.8"
 
diff --git a/lib/src/data/from_data.rs b/lib/src/data/from_data.rs
index 329378bc..ee756269 100644
--- a/lib/src/data/from_data.rs
+++ b/lib/src/data/from_data.rs
@@ -1,3 +1,5 @@
+use std::io::Read;
+
 use outcome::{self, IntoOutcome};
 use outcome::Outcome::*;
 use http::Status;
@@ -115,13 +117,13 @@ impl<'a, S, E> IntoOutcome<S, (Status, E), Data> for Result<S, E> {
 ///         // Split the string into two pieces at ':'.
 ///         let (name, age) = match string.find(':') {
 ///             Some(i) => (&string[..i], &string[(i + 1)..]),
-///             None => return Failure((Status::BadRequest, "Missing ':'.".into()))
+///             None => return Failure((Status::UnprocessableEntity, "':'".into()))
 ///         };
 ///
 ///         // Parse the age.
 ///         let age: u16 = match age.parse() {
 ///             Ok(age) => age,
-///             Err(_) => return Failure((Status::BadRequest, "Bad age.".into()))
+///             Err(_) => return Failure((Status::UnprocessableEntity, "Age".into()))
 ///         };
 ///
 ///         // Return successfully.
@@ -180,3 +182,16 @@ impl<T: FromData> FromData for Option<T> {
         }
     }
 }
+
+impl FromData for String {
+    type Error = ();
+
+    // FIXME: Doc.
+    fn from_data(_: &Request, data: Data) -> Outcome<Self, Self::Error> {
+        let mut string = String::new();
+        match data.open().read_to_string(&mut string) {
+            Ok(_) => Success(string),
+            Err(_) => Failure((Status::UnprocessableEntity, ()))
+        }
+    }
+}
diff --git a/lib/src/http/accept.rs b/lib/src/http/accept.rs
index feb221b1..3d669126 100644
--- a/lib/src/http/accept.rs
+++ b/lib/src/http/accept.rs
@@ -1,19 +1,16 @@
-use http::MediaType;
-use http::parse::parse_accept;
-
 use std::ops::Deref;
 use std::str::FromStr;
 use std::fmt;
 
-#[derive(Debug, PartialEq)]
+use smallvec::SmallVec;
+
+use http::{Header, IntoCollection, MediaType};
+use http::parse::parse_accept;
+
+#[derive(Debug, Clone, PartialEq)]
 pub struct WeightedMediaType(pub MediaType, pub Option<f32>);
 
 impl WeightedMediaType {
-    #[inline(always)]
-    pub fn media_type(&self) -> &MediaType {
-        &self.0
-    }
-
     #[inline(always)]
     pub fn weight(&self) -> Option<f32> {
         self.1
@@ -25,11 +22,23 @@ impl WeightedMediaType {
     }
 
     #[inline(always)]
-    pub fn into_inner(self) -> MediaType {
+    pub fn media_type(&self) -> &MediaType {
+        &self.0
+    }
+
+    #[inline(always)]
+    pub fn into_media_type(self) -> MediaType {
         self.0
     }
 }
 
+impl From<MediaType> for WeightedMediaType {
+    #[inline(always)]
+    fn from(media_type: MediaType) -> WeightedMediaType {
+        WeightedMediaType(media_type, None)
+    }
+}
+
 impl Deref for WeightedMediaType {
     type Target = MediaType;
 
@@ -39,14 +48,55 @@ impl Deref for WeightedMediaType {
     }
 }
 
-/// The HTTP Accept header.
-#[derive(Debug, PartialEq)]
-pub struct Accept(pub Vec<WeightedMediaType>);
+// FIXME: `Static` is needed for `const` items. Need `const SmallVec::new`.
+#[derive(Debug, PartialEq, Clone)]
+pub enum AcceptParams {
+    Static(&'static [WeightedMediaType]),
+    Dynamic(SmallVec<[WeightedMediaType; 1]>)
+}
 
-static ANY: WeightedMediaType = WeightedMediaType(MediaType::Any, None);
+/// The HTTP Accept header.
+#[derive(Debug, Clone, PartialEq)]
+pub struct Accept(AcceptParams);
+
+macro_rules! accept_constructor {
+    ($($name:ident ($check:ident): $str:expr, $t:expr,
+        $s:expr $(; $k:expr => $v:expr)*),+) => {
+        $(
+            #[doc="An `Accept` header with the single media type for <b>"]
+            #[doc=$str] #[doc="</b>: <i>"]
+            #[doc=$t] #[doc="/"] #[doc=$s]
+            #[doc="</i>"]
+            #[allow(non_upper_case_globals)]
+            pub const $name: Accept = Accept(
+                AcceptParams::Static(&[WeightedMediaType(MediaType::$name, None)])
+            );
+         )+
+    };
+}
+
+impl<T: IntoCollection<MediaType>> From<T> for Accept {
+    #[inline(always)]
+    fn from(items: T) -> Accept {
+        Accept(AcceptParams::Dynamic(items.mapped(|item| item.into())))
+    }
+}
 
 impl Accept {
+    #[inline(always)]
+    pub fn new<T: IntoCollection<WeightedMediaType>>(items: T) -> Accept {
+        Accept(AcceptParams::Dynamic(items.into_collection()))
+    }
+
+    // FIXME: IMPLEMENT THIS.
+    // #[inline(always)]
+    // pub fn add<M: Into<WeightedMediaType>>(&mut self, media_type: M) {
+    //     self.0.push(media_type.into());
+    // }
+
     pub fn preferred(&self) -> &WeightedMediaType {
+        static ANY: WeightedMediaType = WeightedMediaType(MediaType::Any, None);
+        //
         // See https://tools.ietf.org/html/rfc7231#section-5.3.2.
         let mut all = self.iter();
         let mut preferred = all.next().unwrap_or(&ANY);
@@ -55,6 +105,7 @@ impl Accept {
                 preferred = current;
             } else if current.weight_or(0.0) > preferred.weight_or(1.0) {
                 preferred = current;
+                // FIXME: Prefer text/html over text/*, for example.
             } else if current.media_type() == preferred.media_type() {
                 if current.weight() == preferred.weight() {
                     let c_count = current.params().filter(|p| p.0 != "q").count();
@@ -71,22 +122,25 @@ impl Accept {
 
     #[inline(always)]
     pub fn first(&self) -> Option<&WeightedMediaType> {
-        if self.0.len() > 0 {
-            Some(&self.0[0])
-        } else {
-            None
-        }
+        self.iter().next()
     }
 
     #[inline(always)]
     pub fn iter<'a>(&'a self) -> impl Iterator<Item=&'a WeightedMediaType> + 'a {
-        self.0.iter()
+        let slice = match self.0 {
+            AcceptParams::Static(slice) => slice,
+            AcceptParams::Dynamic(ref vec) => &vec[..],
+        };
+
+        slice.iter()
     }
 
     #[inline(always)]
     pub fn media_types<'a>(&'a self) -> impl Iterator<Item=&'a MediaType> + 'a {
-        self.0.iter().map(|weighted_mt| weighted_mt.media_type())
+        self.iter().map(|weighted_mt| weighted_mt.media_type())
     }
+
+    known_media_types!(accept_constructor);
 }
 
 impl fmt::Display for Accept {
@@ -110,6 +164,15 @@ impl FromStr for Accept {
     }
 }
 
+/// Creates a new `Header` with name `Accept` and the value set to the HTTP
+/// rendering of this `Accept` header.
+impl Into<Header<'static>> for Accept {
+    #[inline(always)]
+    fn into(self) -> Header<'static> {
+        Header::new("Accept", self.to_string())
+    }
+}
+
 #[cfg(test)]
 mod test {
     use http::{Accept, MediaType};
diff --git a/lib/src/http/content_type.rs b/lib/src/http/content_type.rs
index 8c00ab80..276dc2c0 100644
--- a/lib/src/http/content_type.rs
+++ b/lib/src/http/content_type.rs
@@ -3,7 +3,7 @@ use std::ops::Deref;
 use std::str::FromStr;
 use std::fmt;
 
-use http::{Header, MediaType};
+use http::{IntoCollection, Header, MediaType};
 use http::hyper::mime::Mime;
 
 /// Representation of HTTP Content-Types.
@@ -136,7 +136,7 @@ impl ContentType {
     /// ```rust
     /// use rocket::http::ContentType;
     ///
-    /// let id = ContentType::with_params("application", "x-id", Some(("id", "1")));
+    /// let id = ContentType::with_params("application", "x-id", ("id", "1"));
     /// assert_eq!(id.to_string(), "application/x-id; id=1".to_string());
     /// ```
     ///
@@ -153,11 +153,21 @@ impl ContentType {
     pub fn with_params<T, S, K, V, P>(top: T, sub: S, ps: P) -> ContentType
         where T: Into<Cow<'static, str>>, S: Into<Cow<'static, str>>,
               K: Into<Cow<'static, str>>, V: Into<Cow<'static, str>>,
-              P: IntoIterator<Item=(K, V)>
+              P: IntoCollection<(K, V)>
     {
         ContentType(MediaType::with_params(top, sub, ps))
     }
 
+    #[inline(always)]
+    pub fn media_type(&self) -> &MediaType {
+        &self.0
+    }
+
+    #[inline(always)]
+    pub fn into_media_type(self) -> MediaType {
+        self.0
+    }
+
     known_media_types!(content_types);
 }
 
diff --git a/lib/src/http/known_media_types.rs b/lib/src/http/known_media_types.rs
index 1eb7706e..b28a7799 100644
--- a/lib/src/http/known_media_types.rs
+++ b/lib/src/http/known_media_types.rs
@@ -1,8 +1,8 @@
 macro_rules! known_media_types {
     ($cont:ident) => ($cont! {
-        Any (is_any): "any Content-Type", "*", "*",
+        Any (is_any): "any media type", "*", "*",
         HTML (is_html): "HTML", "text", "html" ; "charset" => "utf-8",
-        Plain (is_plain): "plaintext", "text", "plain" ; "charset" => "utf-8",
+        Plain (is_plain): "plain text", "text", "plain" ; "charset" => "utf-8",
         JSON (is_json): "JSON", "application", "json",
         MsgPack (is_msgpack): "MessagePack", "application", "msgpack",
         Form (is_form): "forms", "application", "x-www-form-urlencoded",
diff --git a/lib/src/http/media_type.rs b/lib/src/http/media_type.rs
index 53e09a31..07a8b7f4 100644
--- a/lib/src/http/media_type.rs
+++ b/lib/src/http/media_type.rs
@@ -3,6 +3,7 @@ use std::str::FromStr;
 use std::fmt;
 use std::hash::{Hash, Hasher};
 
+use http::IntoCollection;
 use http::ascii::{uncased_eq, UncasedAsciiRef};
 use http::parse::{IndexedStr, parse_media_type};
 
@@ -17,7 +18,6 @@ struct MediaParam {
 // FIXME: `Static` is needed for `const` items. Need `const SmallVec::new`.
 #[derive(Debug, Clone)]
 pub enum MediaParams {
-    Empty,
     Static(&'static [(IndexedStr, IndexedStr)]),
     Dynamic(SmallVec<[(IndexedStr, IndexedStr); 2]>)
 }
@@ -142,7 +142,7 @@ impl MediaType {
             source: None,
             top: IndexedStr::Concrete(top.into()),
             sub: IndexedStr::Concrete(sub.into()),
-            params: MediaParams::Empty,
+            params: MediaParams::Static(&[]),
         }
     }
 
@@ -157,7 +157,7 @@ impl MediaType {
     /// ```rust
     /// use rocket::http::MediaType;
     ///
-    /// let id = MediaType::with_params("application", "x-id", Some(("id", "1")));
+    /// let id = MediaType::with_params("application", "x-id", ("id", "1"));
     /// assert_eq!(id.to_string(), "application/x-id; id=1".to_string());
     /// ```
     ///
@@ -174,15 +174,13 @@ impl MediaType {
     pub fn with_params<T, S, K, V, P>(top: T, sub: S, ps: P) -> MediaType
         where T: Into<Cow<'static, str>>, S: Into<Cow<'static, str>>,
               K: Into<Cow<'static, str>>, V: Into<Cow<'static, str>>,
-              P: IntoIterator<Item=(K, V)>
+              P: IntoCollection<(K, V)>
     {
-        let mut params = SmallVec::new();
-        for (key, val) in ps {
-            params.push((
-                IndexedStr::Concrete(key.into()),
-                IndexedStr::Concrete(val.into())
-            ))
-        }
+        let params = ps.mapped(|(key, val)| (
+            IndexedStr::Concrete(key.into()),
+            IndexedStr::Concrete(val.into())
+        ));
+
 
         MediaType {
             source: None,
@@ -259,7 +257,6 @@ impl MediaType {
         let param_slice = match self.params {
             MediaParams::Static(slice) => slice,
             MediaParams::Dynamic(ref vec) => &vec[..],
-            MediaParams::Empty => &[]
         };
 
         param_slice.iter()
diff --git a/lib/src/http/mod.rs b/lib/src/http/mod.rs
index 1d256db0..94999693 100644
--- a/lib/src/http/mod.rs
+++ b/lib/src/http/mod.rs
@@ -36,3 +36,48 @@ pub use self::header::{Header, HeaderMap};
 pub use self::media_type::MediaType;
 pub use self::cookies::*;
 pub use self::session::*;
+
+use smallvec::{Array, SmallVec};
+
+pub trait IntoCollection<T> {
+    fn into_collection<A: Array<Item=T>>(self) -> SmallVec<A>;
+    fn mapped<U, F: FnMut(T) -> U, A: Array<Item=U>>(self, f: F) -> SmallVec<A>;
+}
+
+impl<T> IntoCollection<T> for T {
+    #[inline]
+    fn into_collection<A: Array<Item=T>>(self) -> SmallVec<A> {
+        let mut vec = SmallVec::new();
+        vec.push(self);
+        vec
+    }
+
+    #[inline(always)]
+    fn mapped<U, F: FnMut(T) -> U, A: Array<Item=U>>(self, mut f: F) -> SmallVec<A> {
+        f(self).into_collection()
+    }
+}
+
+impl<T> IntoCollection<T> for Vec<T> {
+    #[inline(always)]
+    fn into_collection<A: Array<Item=T>>(self) -> SmallVec<A> {
+        SmallVec::from_vec(self)
+    }
+
+    #[inline]
+    fn mapped<U, F: FnMut(T) -> U, A: Array<Item=U>>(self, mut f: F) -> SmallVec<A> {
+        self.into_iter().map(|item| f(item)).collect()
+    }
+}
+
+impl<'a, T: Clone> IntoCollection<T> for &'a [T] {
+    #[inline(always)]
+    fn into_collection<A: Array<Item=T>>(self) -> SmallVec<A> {
+        self.iter().cloned().collect()
+    }
+
+    #[inline]
+    fn mapped<U, F: FnMut(T) -> U, A: Array<Item=U>>(self, mut f: F) -> SmallVec<A> {
+        self.iter().cloned().map(|item| f(item)).collect()
+    }
+}
diff --git a/lib/src/http/parse/accept.rs b/lib/src/http/parse/accept.rs
index 2733f0fe..f40c77ad 100644
--- a/lib/src/http/parse/accept.rs
+++ b/lib/src/http/parse/accept.rs
@@ -5,7 +5,7 @@ use http::parse::checkers::is_whitespace;
 use http::parse::media_type::media_type;
 use http::{MediaType, Accept, WeightedMediaType};
 
-fn q_value<'a>(_: &'a str, media_type: &MediaType) -> ParseResult<&'a str, Option<f32>> {
+fn q<'a>(_: &'a str, media_type: &MediaType) -> ParseResult<&'a str, Option<f32>> {
     match media_type.params().next() {
         Some(("q", value)) if value.len() <= 4 => match value.parse::<f32>().ok() {
             Some(q) if q > 1.0 => ParseError::custom("accept", "q value must be <= 1.0"),
@@ -22,11 +22,11 @@ fn accept<'a>(input: &mut &'a str) -> ParseResult<&'a str, Accept> {
     repeat_while!(eat(','), {
         skip_while(is_whitespace);
         let media_type = media_type();
-        let weight = q_value(&media_type);
+        let weight = q(&media_type);
         media_types.push(WeightedMediaType(media_type, weight));
     });
 
-    Accept(media_types)
+    Accept::new(media_types)
 }
 
 pub fn parse_accept(mut input: &str) -> Result<Accept, ParseError<&str>> {
diff --git a/lib/src/request/request.rs b/lib/src/request/request.rs
index 2c9b7312..6d607463 100644
--- a/lib/src/request/request.rs
+++ b/lib/src/request/request.rs
@@ -323,6 +323,8 @@ impl<'r> Request<'r> {
     /// ```
     #[inline(always)]
     pub fn content_type(&self) -> Option<ContentType> {
+        // FIXME: Don't reparse each time! Use RC? Smarter than that?
+        // Use state::Storage!
         self.headers().get_one("Content-Type").and_then(|value| value.parse().ok())
     }
 
@@ -336,6 +338,20 @@ impl<'r> Request<'r> {
         self.headers().get_one("Accept").and_then(|mut v| media_type(&mut v).ok())
     }
 
+    #[inline(always)]
+    pub fn format(&self) -> Option<MediaType> {
+        if self.method.supports_payload() {
+            self.content_type().map(|ct| ct.into_media_type())
+        } else {
+            // FIXME: Should we be using `accept_first` or `preferred`? Or
+            // should we be checking neither and instead pass things through
+            // where the client accepts the thing at all?
+            self.accept()
+                .map(|accept| accept.preferred().media_type().clone())
+                .or(Some(MediaType::Any))
+        }
+    }
+
     /// Retrieves and parses into `T` the 0-indexed `n`th dynamic parameter from
     /// the request. Returns `Error::NoKey` if `n` is greater than the number of
     /// params. Returns `Error::BadParse` if the parameter type `T` can't be
@@ -438,9 +454,8 @@ impl<'r> Request<'r> {
     }
 
     /// Get the managed state container, if it exists. For internal use only!
-    /// FIXME: Expose?
     #[inline(always)]
-    pub(crate) fn get_state<T: Send + Sync + 'static>(&self) -> Option<&'r T> {
+    pub fn get_state<T: Send + Sync + 'static>(&self) -> Option<&'r T> {
         self.preset().managed_state.try_get()
     }
 
diff --git a/lib/src/router/collider.rs b/lib/src/router/collider.rs
index f08b2534..a38b408c 100644
--- a/lib/src/router/collider.rs
+++ b/lib/src/router/collider.rs
@@ -113,12 +113,13 @@ impl<'r> Collider<Request<'r>> for Route {
         self.method == req.method()
             && self.path.collides_with(req.uri())
             && self.path.query().map_or(true, |_| req.uri().query().is_some())
-            // FIXME: On payload requests, check Content-Type, else Accept.
-            && match (req.content_type().as_ref(), self.format.as_ref()) {
-                (Some(mt_a), Some(mt_b)) => mt_a.collides_with(mt_b),
-                (Some(_), None) => true,
-                (None, Some(_)) => false,
-                (None, None) => true
+            // FIXME: Avoid calling `format` is `self.format` == None.
+            && match self.format.as_ref() {
+                Some(mt_a) => match req.format().as_ref() {
+                    Some(mt_b) => mt_a.collides_with(mt_b),
+                    None => false
+                },
+                None => true
             }
     }
 }
@@ -132,7 +133,7 @@ mod tests {
     use data::Data;
     use handler::Outcome;
     use router::route::Route;
-    use http::{Method, MediaType, ContentType};
+    use http::{Method, MediaType, ContentType, Accept};
     use http::uri::URI;
     use http::Method::*;
 
@@ -362,15 +363,19 @@ mod tests {
         assert!(!r_mt_mt_collide(Get, "text/html", Get, "text/css"));
     }
 
-    fn req_route_mt_collide<S1, S2>(m1: Method, mt1: S1, m2: Method, mt2: S2) -> bool
+    fn req_route_mt_collide<S1, S2>(m: Method, mt1: S1, mt2: S2) -> bool
         where S1: Into<Option<&'static str>>, S2: Into<Option<&'static str>>
     {
-        let mut req = Request::new(m1, "/");
+        let mut req = Request::new(m, "/");
         if let Some(mt_str) = mt1.into() {
-            req.replace_header(mt_str.parse::<ContentType>().unwrap());
+            if m.supports_payload() {
+                req.replace_header(mt_str.parse::<ContentType>().unwrap());
+            } else {
+                req.replace_header(mt_str.parse::<Accept>().unwrap());
+            }
         }
 
-        let mut route = Route::new(m2, "/", dummy_handler);
+        let mut route = Route::new(m, "/", dummy_handler);
         if let Some(mt_str) = mt2.into() {
             route.format = Some(mt_str.parse::<MediaType>().unwrap());
         }
@@ -380,24 +385,41 @@ mod tests {
 
     #[test]
     fn test_req_route_mt_collisions() {
-        assert!(req_route_mt_collide(Get, "application/json", Get, "application/json"));
-        assert!(req_route_mt_collide(Get, "application/json", Get, "application/*"));
-        assert!(req_route_mt_collide(Get, "application/json", Get, "*/json"));
-        assert!(req_route_mt_collide(Get, "text/html", Get, "text/html"));
-        assert!(req_route_mt_collide(Get, "text/html", Get, "*/*"));
+        assert!(req_route_mt_collide(Post, "application/json", "application/json"));
+        assert!(req_route_mt_collide(Post, "application/json", "application/*"));
+        assert!(req_route_mt_collide(Post, "application/json", "*/json"));
+        assert!(req_route_mt_collide(Post, "text/html", "*/*"));
 
-        assert!(req_route_mt_collide(Get, "text/html", Get, None));
-        assert!(req_route_mt_collide(Get, None, Get, None));
-        assert!(req_route_mt_collide(Get, "application/json", Get, None));
-        assert!(req_route_mt_collide(Get, "x-custom/anything", Get, None));
+        assert!(req_route_mt_collide(Get, "application/json", "application/json"));
+        assert!(req_route_mt_collide(Get, "text/html", "text/html"));
+        assert!(req_route_mt_collide(Get, "text/html", "*/*"));
+        assert!(req_route_mt_collide(Get, None, "text/html"));
+        assert!(req_route_mt_collide(Get, None, "*/*"));
+        assert!(req_route_mt_collide(Get, None, "application/json"));
 
-        assert!(!req_route_mt_collide(Get, "application/json", Get, "text/html"));
-        assert!(!req_route_mt_collide(Get, "application/json", Get, "text/*"));
-        assert!(!req_route_mt_collide(Get, "application/json", Get, "*/xml"));
+        assert!(req_route_mt_collide(Post, "text/html", None));
+        assert!(req_route_mt_collide(Post, "application/json", None));
+        assert!(req_route_mt_collide(Post, "x-custom/anything", None));
+        assert!(req_route_mt_collide(Post, None, None));
 
-        assert!(!req_route_mt_collide(Get, None, Get, "text/html"));
-        assert!(!req_route_mt_collide(Get, None, Get, "*/*"));
-        assert!(!req_route_mt_collide(Get, None, Get, "application/json"));
+        assert!(req_route_mt_collide(Get, "text/html", None));
+        assert!(req_route_mt_collide(Get, "application/json", None));
+        assert!(req_route_mt_collide(Get, "x-custom/anything", None));
+        assert!(req_route_mt_collide(Get, None, None));
+
+        assert!(req_route_mt_collide(Get, "text/html, text/plain", "text/html"));
+        assert!(req_route_mt_collide(Get, "text/html; q=0.5, text/xml", "text/xml"));
+
+        assert!(!req_route_mt_collide(Post, "application/json", "text/html"));
+        assert!(!req_route_mt_collide(Post, "application/json", "text/*"));
+        assert!(!req_route_mt_collide(Post, "application/json", "*/xml"));
+        assert!(!req_route_mt_collide(Get, "application/json", "text/html"));
+        assert!(!req_route_mt_collide(Get, "application/json", "text/*"));
+        assert!(!req_route_mt_collide(Get, "application/json", "*/xml"));
+
+        assert!(!req_route_mt_collide(Post, None, "text/html"));
+        assert!(!req_route_mt_collide(Post, None, "*/*"));
+        assert!(!req_route_mt_collide(Post, None, "application/json"));
     }
 
     fn req_route_path_collide(a: &'static str, b: &'static str) -> bool {